MrCool mini-split error codes by generation
99 codes for DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen, DIY 5th Gen Multi-Zone, DIY 5th Gen Cassette, DIY Hybrid Air Handler, Olympus Ducted, DIY E Star 4th Gen, DIY 4th Gen Multi-Zone, DIY 4th Gen Cassette, Advantage 4th Gen, DIY E Star 3rd Gen, each with the wording and page from MrCool's manuals.
All MrCool codes
Meanings are quoted from MrCool's manuals. The "Who" column is our reading of themanual's remedy: whether an owner can do the first checks, or the fix belongs to a licensed technician.
| Code | Manual meaning | Series | Who | Source |
|---|---|---|---|---|
| DF | “Defrost” What to check Display mode. Marked “Normal Display, not error code” in the DIY Select, Easy Pro, Advantage 5th Gen and DIY 5th Gen Multi-Zone tables and in the hybrid air handler and Olympus outdoor board tables; the DIY 4th Gen multi-zone outdoor table says “Normal Display, not an error code”. The DIY 5th Gen single-zone tables list it among the error codes without that mark. Advantage prints “dF”; the hybrid air handler and DIY 4th Gen multi-zone tables say “Defrosting”. Also in the 5th Gen outdoor board tables. The DIY E Star 3rd Gen display section says the unit shows “dF” while defrosting (DIY E Star 3rd Gen Installation & Owner's Manual, p. 6). | DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen, DIY 5th Gen Multi-Zone, DIY Hybrid Air Handler, Olympus Ducted, DIY 4th Gen Multi-Zone | Owner can check | DIY 5th Gen owner's p. 39; Select owner's p. 41; Easy Pro owner's p. 41; Advantage 5th Gen owner's p. 46; DIY 5th Gen multi-zone owner's p. 48; Hybrid air handler owner's p. 57; Olympus ducted owner's p. 44; DIY 4th Gen multi-zone owner's p. 50 |
| CL | “Active Clean” The display shows CL while the Active Clean function runs; after 20 to 45 minutes the unit turns off and cancels the function (DIY 5th Gen Single-Zone Installation & Owner's Manual, p. 11). Marked “Normal Display, not error code” in the Select, Easy Pro and Advantage 5th Gen tables and the DIY 4th Gen multi-zone guide; the DIY 5th Gen single-zone table has no mark. Printed “Cl” in the DIY, Select and Easy Pro tables. | DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen, DIY 4th Gen Multi-Zone | Owner can check | DIY 5th Gen owner's p. 39; Select owner's p. 41; Easy Pro owner's p. 41; Advantage 5th Gen owner's p. 46; DIY 4th Gen multi-zone guide Troubleshooting 4 |
| CL | “Filter cleaning reminder (power on display for 15 seconds)” A reminder, marked “Normal Display, not error code” in the Advantage 5th Gen table and the DIY 4th Gen multi-zone guide. The Advantage 4th Gen manual: after 240 hours of use the display flashes “CL” as a reminder to clean the filter; to reset, press the LED button on the remote 4 times or the MANUAL CONTROL button 3 times (Advantage 4th Gen Owner's and Installation Manual, p. 13). The DIY E Star 4th Gen manual gives the same 240 hours and reset (DIY E Star 4th Gen Installation & Owner's Manual, p. 13). | Advantage 5th Gen, DIY 4th Gen Multi-Zone | Owner can check | Advantage 5th Gen owner's p. 46; DIY 4th Gen multi-zone guide Troubleshooting 4 |
| nF | “Filter replacement reminder (power on display for 15 seconds) (For some models)” A reminder, marked “Normal Display, not error code” in the Advantage 5th Gen table and the DIY 4th Gen multi-zone guide. The DIY 4th Gen multi-zone guide prints it without “(For some models)”. After 2,880 hours of use the display flashes “nF” as a reminder to replace the filter (Advantage 4th Gen Owner's and Installation Manual, p. 13); the DIY E Star 4th Gen manual resets it like CL, with the LED button 4 times or MANUAL CONTROL 3 times (DIY E Star 4th Gen Installation & Owner's Manual, p. 13). | Advantage 5th Gen, DIY 4th Gen Multi-Zone | Owner can check | Advantage 5th Gen owner's p. 46; DIY 4th Gen multi-zone guide Troubleshooting 4 |
| FP | “Heating in Room Temperature under 46.4°F (8°C)” The display list says it shows when the 46°F (8°C) heating feature is turned on (DIY 5th Gen Single-Zone Installation & Owner's Manual, p. 10). Marked “Normal Display, not error code” in the Select, Easy Pro and Advantage 5th Gen tables and the DIY 4th Gen multi-zone guide; the DIY 5th Gen single-zone table has no mark. The DIY 4th Gen multi-zone guide says “Heating in room temperature under 8°C”. | DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen, DIY 4th Gen Multi-Zone | Owner can check | DIY 5th Gen owner's p. 39; Select owner's p. 41; Easy Pro owner's p. 41; Advantage 5th Gen owner's p. 46; DIY 4th Gen multi-zone guide Troubleshooting 4 |
| FC | “Forced Cooling” The cassette and Olympus indoor display tables print “Forced Cooling (Not an error code)”; the Select, Easy Pro, Advantage 5th Gen, DIY 5th Gen Multi-Zone and DIY 4th Gen multi-zone tables and the hybrid air handler and Olympus outdoor board tables mark it “Normal Display, not error code”; the DIY 5th Gen single-zone tables have no mark. Forced cooling is started with the MANUAL CONTROL button, which the manual says is for testing and emergency operation only; the remote control restores regular operation (DIY 5th Gen Single-Zone Installation & Owner's Manual, p. 12). | DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen, DIY 5th Gen Multi-Zone, DIY 5th Gen Cassette, DIY Hybrid Air Handler, Olympus Ducted, DIY 4th Gen Multi-Zone | Owner can check | DIY 5th Gen owner's p. 39; Select owner's p. 41; Easy Pro owner's p. 41; Advantage 5th Gen owner's p. 46; DIY 5th Gen multi-zone owner's p. 48; DIY 5th Gen cassette owner's p. 45; Hybrid air handler owner's p. 57; Olympus ducted owner's p. 43; DIY 4th Gen multi-zone owner's p. 50 |
| AP | “AP Mode of Wifi Connection” What to check Wi-Fi setup mode. Marked “Normal Display, not error code” in the Select, Easy Pro and Advantage 5th Gen tables and the DIY 4th Gen multi-zone guide; the DIY 5th Gen single-zone table has no mark. DIY Select and Easy Pro print “Wi-Fi”; Advantage and the 4th Gen guide print “WIFI”. The remote control manual says AP mode is used to complete wireless network configuration and is entered by pressing the LED button seven times within ten seconds (Mini-Split Remote Control Owner's Manual, p. 10). | DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen, DIY 4th Gen Multi-Zone | Owner can check | DIY 5th Gen owner's p. 39; Select owner's p. 41; Easy Pro owner's p. 41; Advantage 5th Gen owner's p. 46; DIY 4th Gen multi-zone guide Troubleshooting 4 |
| CP | “Remote Switched Off” The DIY 4th Gen multi-zone display list says it shows when the remote controller is switched off (DIY 4th Gen Multi-Zone Installation & Owner's Manual, p. 8). The 5th Gen manuals give no other explanation. Marked “Normal Display, not error code” in the Select, Easy Pro and Advantage 5th Gen tables and the DIY 4th Gen multi-zone guide; the DIY 5th Gen single-zone table has no mark. | DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen, DIY 4th Gen Multi-Zone | Owner can check | DIY 5th Gen owner's p. 39; Select owner's p. 41; Easy Pro owner's p. 41; Advantage 5th Gen owner's p. 46; DIY 4th Gen multi-zone guide Troubleshooting 4 |
| -- | “IDUs Mode Conflict (Multi-Zone)” Printed “----”. Indoor units on one multi-zone system are set to conflicting modes: if one indoor unit selects heat mode, the other running units stop and display “--” (units with a display window only) (DIY 5th Gen Multi-Zone Installation & Owner's Manual, p. 43). | DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen, DIY 5th Gen Cassette, DIY Hybrid Air Handler, Olympus Ducted | Owner can check | DIY 5th Gen owner's p. 39; Select owner's p. 41; Easy Pro owner's p. 41; Advantage 5th Gen owner's p. 47; DIY 5th Gen cassette owner's p. 45; Hybrid air handler owner's p. 56; Olympus ducted owner's p. 43 |
| -- | “Indoor units mode conflict (match with multi outdoor unit).” Operation lamp 1 flash, timer lamp on. On models with a display window, “--” appears when HEAT on one indoor unit stops the others (DIY 4th Gen Multi-Zone Installation & Owner's Manual, p. 14). | DIY E Star 4th Gen, DIY 4th Gen Multi-Zone, DIY 4th Gen Cassette, Advantage 4th Gen | Owner can check | E Star 4th Gen owner's p. 41; DIY 4th Gen multi-zone owner's p. 49; DIY 4th Gen cassette owner's p. 56; Advantage 4th Gen service Troubleshooting 5 |
| EH 00 | “IDU EEPROM Malfunction” Service manual: the indoor board's main chip gets no feedback from the EEPROM chip (DIY 5th Gen Single-Zone Service Manual, p. 54). | DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen, DIY 5th Gen Cassette, DIY Hybrid Air Handler, Olympus Ducted | Owner checks, then technician | DIY 5th Gen owner's p. 39; Select owner's p. 41; Easy Pro owner's p. 41; Advantage 5th Gen owner's p. 46; DIY 5th Gen cassette owner's p. 45; Hybrid air handler owner's p. 56; Olympus ducted owner's p. 43 |
| EH 00 | “Indoor unit EEPROM parameter error.” Operation lamp 1 flash, timer lamp off. The 4th Gen cassette and Advantage tables print the code as “EH 00/EH 0A”. | DIY E Star 4th Gen, DIY 4th Gen Multi-Zone, DIY 4th Gen Cassette, Advantage 4th Gen | Technician | E Star 4th Gen owner's p. 41; DIY 4th Gen multi-zone owner's p. 49; DIY 4th Gen cassette owner's p. 55; Advantage 4th Gen service Troubleshooting 5 |
| EH 02 | “Zero-Crossing Signal Detection Error” Advantage prints “Zero-crossing signal detection”. Service manual: the board receives no zero-crossing signal feedback for 4 minutes, or the signal interval is abnormal (DIY 5th Gen Single-Zone Service Manual, p. 58). | DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen | Owner checks, then technician | DIY 5th Gen owner's p. 39; Select owner's p. 41; Easy Pro owner's p. 41; Advantage 5th Gen owner's p. 46 |
| EH 02 | “Zero-crossing signal detection error (for some models).” Operation lamp 3 flashes, timer lamp off. | DIY E Star 4th Gen, DIY 4th Gen Multi-Zone, Advantage 4th Gen | Technician | E Star 4th Gen owner's p. 41; DIY 4th Gen multi-zone owner's p. 49; Advantage 4th Gen service Troubleshooting 5 |
| EH 03 | “IDU Fan Speed Out of Control” Service manual: the indoor fan speed stays too low or too high for a period of time, the code shows and the unit turns off (DIY 5th Gen Single-Zone Service Manual, p. 59). | DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen, DIY 5th Gen Cassette, DIY Hybrid Air Handler, Olympus Ducted | Owner checks, then technician | DIY 5th Gen owner's p. 39; Select owner's p. 41; Easy Pro owner's p. 41; Advantage 5th Gen owner's p. 46; DIY 5th Gen cassette owner's p. 45; Hybrid air handler owner's p. 56; Olympus ducted owner's p. 43 |
| EH 03 | “The indoor fan speed is operating outside of the normal range.” Operation lamp 4 flashes, timer lamp off. The cassette table adds “(for some models)”. | DIY E Star 4th Gen, DIY 4th Gen Multi-Zone, DIY 4th Gen Cassette, Advantage 4th Gen | Technician | E Star 4th Gen owner's p. 41; DIY 4th Gen multi-zone owner's p. 49; DIY 4th Gen cassette owner's p. 55; Advantage 4th Gen service Troubleshooting 5 |
| EH 06 | “IDU main control board and display board communication error” Only in the Advantage 5th Gen owner's manual table. Every other 5th Gen table, including the Advantage service manual's, prints this meaning as EH 0B (Advantage 5th Gen Service Manual, p. 53). | Advantage 5th Gen | Owner checks, then technician | Advantage 5th Gen owner's p. 46 |
| EH 0A | “Indoor EEPROM Parameter Error” Cassette, hybrid air handler and Olympus: “IDU EEPROM parameter error”. Advantage prints the code “EH OA”. | DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen, DIY 5th Gen Cassette, DIY Hybrid Air Handler, Olympus Ducted | Owner checks, then technician | DIY 5th Gen owner's p. 39; Select owner's p. 41; Easy Pro owner's p. 41; Advantage 5th Gen owner's p. 46; DIY 5th Gen cassette owner's p. 45; Hybrid air handler owner's p. 56; Olympus ducted owner's p. 43 |
| EH 0B | “IDU Main Control Board & Display Board Communication Error” The Advantage 5th Gen owner's manual prints this line as EH 06 (Advantage 5th Gen Installation & Owner's Manual, p. 46). Service manual: the indoor board receives no feedback from the display board (DIY 5th Gen Single-Zone Service Manual, p. 66). | DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen, DIY Hybrid Air Handler | Owner checks, then technician | DIY 5th Gen owner's p. 39; Select owner's p. 41; Easy Pro owner's p. 41; Advantage 5th Gen service p. 53; Hybrid air handler owner's p. 56 |
| EH 0B | “Indoor PCB / Display board communication error.” Operation lamp 9 flashes, timer lamp off. Advantage adds “(for some models)”. The cassette table says “Communication error between display board and main board”. | DIY E Star 4th Gen, DIY 4th Gen Cassette, Advantage 4th Gen | Technician | E Star 4th Gen owner's p. 41; DIY 4th Gen cassette owner's p. 55; Advantage 4th Gen service Troubleshooting 5 |
| EH 0E | “Water-level alarm malfunction” | DIY 5th Gen Cassette, DIY Hybrid Air Handler, Olympus Ducted | Owner checks, then technician | DIY 5th Gen cassette owner's p. 45; Hybrid air handler owner's p. 56; Olympus ducted owner's p. 43 |
| EH 0E | “Water-level alarm malfunction” Operation lamp 13 flashes, timer lamp off. | DIY 4th Gen Cassette | Technician | DIY 4th Gen cassette owner's p. 55 |
| EH 12 | “Main unit or secondary unit malfunction” Olympus: “Main unit or secondary units malfunction”. | DIY 5th Gen Cassette, Olympus Ducted | Owner checks, then technician | DIY 5th Gen cassette owner's p. 45; Olympus ducted owner's p. 43 |
| EH 31 | “Upper indoor fan speed is operating outside of the normal range(for new console type)” Operation lamp 4 flashes, timer lamp off. | DIY 4th Gen Cassette | Technician | DIY 4th Gen cassette owner's p. 55 |
| EH 32 | “Lower indoor fan speed is operating outside of the normal range(for new console type)” Operation lamp 4 flashes, timer lamp off. | DIY 4th Gen Cassette | Technician | DIY 4th Gen cassette owner's p. 55 |
| EH 3A | “External fan DC bus voltage is too low protection” Hybrid air handler: “External fan DC bus voltage is too low”. | DIY 5th Gen Cassette, DIY Hybrid Air Handler, Olympus Ducted | Owner checks, then technician | DIY 5th Gen cassette owner's p. 45; Hybrid air handler owner's p. 56; Olympus ducted owner's p. 43 |
| EH 3A | “External fan DC bus voltage is too low protection(for some models)” Operation lamp 4 flashes, timer lamp off. | DIY 4th Gen Cassette | Technician | DIY 4th Gen cassette owner's p. 56 |
| EH 3B | “External fan DC bus voltage is too high fault” Hybrid air handler: “External fan DC bus voltage is too high”. | DIY 5th Gen Cassette, DIY Hybrid Air Handler, Olympus Ducted | Owner checks, then technician | DIY 5th Gen cassette owner's p. 45; Hybrid air handler owner's p. 56; Olympus ducted owner's p. 43 |
| EH 3B | “External fan DC bus voltage is too high fault(for some models)” Operation lamp 4 flashes, timer lamp off. | DIY 4th Gen Cassette | Technician | DIY 4th Gen cassette owner's p. 56 |
| EH 60 | “IDU Room Temperature Sensor (T1) Error” Advantage, cassette, hybrid air handler and Olympus: “IDU room temp. sensor (T1) error”. Service manual: the sensor's sampling voltage is below 0.06 V or above 4.94 V (DIY 5th Gen Single-Zone Service Manual, p. 63). | DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen, DIY 5th Gen Cassette, DIY Hybrid Air Handler, Olympus Ducted | Owner checks, then technician | DIY 5th Gen owner's p. 39; Select owner's p. 41; Easy Pro owner's p. 41; Advantage 5th Gen owner's p. 46; DIY 5th Gen cassette owner's p. 45; Hybrid air handler owner's p. 56; Olympus ducted owner's p. 43 |
| EH 60 | “Indoor room temperature sensor T1 is in open circuit or has short circuited.” Operation lamp 6 flashes, timer lamp off. | DIY E Star 4th Gen, DIY 4th Gen Multi-Zone, DIY 4th Gen Cassette, Advantage 4th Gen | Technician | E Star 4th Gen owner's p. 41; DIY 4th Gen multi-zone owner's p. 49; DIY 4th Gen cassette owner's p. 55; Advantage 4th Gen service Troubleshooting 5 |
| EH 61 | “IDU Pipe Temperature (T2) Sensor Error” The same T2 sensor is named differently by series: “IDU Coil Temperature Sensor (T2) Error” (DIY Select, Easy Pro), “IDU pipe temp. (T2) sensor error” (Advantage), “IDU evaporator coil temp. sensor (T2) error” (cassette, Olympus), “IDU coil temp. sensor (T2) error” (hybrid air handler). | DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen, DIY 5th Gen Cassette, DIY Hybrid Air Handler, Olympus Ducted | Owner checks, then technician | DIY 5th Gen owner's p. 39; Select owner's p. 41; Easy Pro owner's p. 41; Advantage 5th Gen owner's p. 46; DIY 5th Gen cassette owner's p. 45; Hybrid air handler owner's p. 56; Olympus ducted owner's p. 43 |
| EH 61 | “Evaporator coil temperature sensor T2 is in open circuit or has short circuited.” Operation lamp 6 flashes, timer lamp off. | DIY E Star 4th Gen, DIY 4th Gen Multi-Zone, DIY 4th Gen Cassette, Advantage 4th Gen | Technician | E Star 4th Gen owner's p. 41; DIY 4th Gen multi-zone owner's p. 49; DIY 4th Gen cassette owner's p. 55; Advantage 4th Gen service Troubleshooting 5 |
| EH 62/EH 66 | “Evaporator coil inlet temperature sensor T2B is in open circuit or short circuit” Printed as one row, “EH 62 / EH 66”. | DIY Hybrid Air Handler | Technician | Hybrid air handler owner's p. 56 |
| EH 65 | “Evaporator coil temperature sensor T2A is in open circuit or short circuit” | DIY Hybrid Air Handler | Technician | Hybrid air handler owner's p. 56 |
| EH B3 | “Communication malfunction between wire and master control” Listed under the error display on the two-way communication wired controller. | DIY Hybrid Air Handler | Technician | Hybrid air handler owner's p. 57 |
| EH B3 | “Communication error between wire controller and indoor unit((for KJR-120X series wired controller)” Printed with a double parenthesis as shown. | DIY 4th Gen Cassette | Technician | DIY 4th Gen cassette owner's p. 56 |
| EH BA | “Communication error between the indoor unit and the external fan module” Olympus: “Communication error between the indoor unit and external fan module”; hybrid air handler: “Communication malfunction between indoor unit and external fan module”. | DIY 5th Gen Cassette, DIY Hybrid Air Handler, Olympus Ducted | Owner checks, then technician | DIY 5th Gen cassette owner's p. 45; Hybrid air handler owner's p. 56; Olympus ducted owner's p. 43 |
| EH BA | “Communication malfunction between external fan module and indoor unit(for some models)” No lamp pattern printed for this row. | DIY 4th Gen Cassette | Technician | DIY 4th Gen cassette owner's p. 56 |
| EH C1 | “Refrigerant Sensor Detects Leakage” Only for units with a refrigerant sensor. The buzzer beeps for 5 to 6 minutes, and any button on the remote stops it (DIY 5th Gen Single-Zone Installation & Owner's Manual, p. 11). Not in the DIY Select or Easy Pro owner's manual tables; their service manuals list it. Service manual: the sensor reads a concentration of at least 10% of LFL for 10 seconds, or at least 20% of LFL (DIY 5th Gen Single-Zone Service Manual, p. 69). | DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen, DIY 5th Gen Multi-Zone, DIY 5th Gen Cassette, DIY Hybrid Air Handler, Olympus Ducted | Technician | DIY 5th Gen owner's p. 39; Select service p. 42; Easy Pro service p. 42; Advantage 5th Gen owner's p. 46; DIY 5th Gen multi-zone owner's p. 48; DIY 5th Gen cassette owner's p. 45; Hybrid air handler owner's p. 56; Olympus ducted owner's p. 43 |
| EH C2 | “Refrigerant Sensor is Out of Range & Leakage is Detected” Only for units with a refrigerant sensor; the buzzer sounds as for EH C1 (DIY 5th Gen Single-Zone Installation & Owner's Manual, p. 11). Advantage, cassette, hybrid air handler and Olympus spell out “and”. Not in the DIY Select or Easy Pro owner's manual tables; their service manuals list it. | DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen, DIY 5th Gen Cassette, DIY Hybrid Air Handler, Olympus Ducted | Technician | DIY 5th Gen owner's p. 39; Select service p. 42; Easy Pro service p. 42; Advantage 5th Gen owner's p. 46; DIY 5th Gen cassette owner's p. 45; Hybrid air handler owner's p. 56; Olympus ducted owner's p. 43 |
| EH C3 | “Refrigerant Sensor is Out of Range” Only for units with a refrigerant sensor (DIY 5th Gen Single-Zone Installation & Owner's Manual, p. 11). Not in the DIY Select or Easy Pro owner's manual tables; their service manuals list it. | DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen, DIY 5th Gen Cassette, DIY Hybrid Air Handler, Olympus Ducted | Technician | DIY 5th Gen owner's p. 39; Select service p. 42; Easy Pro service p. 42; Advantage 5th Gen owner's p. 46; DIY 5th Gen cassette owner's p. 45; Hybrid air handler owner's p. 56; Olympus ducted owner's p. 43 |
| EL 01 | “IDU & ODU Communication Error” What to check Also in the outdoor board tables (DIY 5th Gen Single-Zone Installation & Owner's Manual, p. 40). Service manual: the indoor unit cannot communicate with the outdoor unit (DIY 5th Gen Single-Zone Service Manual, p. 56). The DIY E Star 3rd Gen manual lists a communication error between the units as E1. | DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen, DIY 5th Gen Multi-Zone, DIY 5th Gen Cassette, DIY Hybrid Air Handler, Olympus Ducted | Owner checks, then technician | DIY 5th Gen owner's p. 39; Select owner's p. 41; Easy Pro owner's p. 41; Advantage 5th Gen owner's p. 46; DIY 5th Gen multi-zone owner's p. 48; DIY 5th Gen cassette owner's p. 45; Hybrid air handler owner's p. 56; Olympus ducted owner's p. 43 |
| EL 01 | “Indoor / outdoor unit communication error.” What to check Operation lamp 2 flashes, timer lamp off. The DIY 4th Gen multi-zone outdoor table says “Indoor / outdoor units communication error” (DIY 4th Gen Multi-Zone Installation & Owner's Manual, p. 50). | DIY E Star 4th Gen, DIY 4th Gen Multi-Zone, DIY 4th Gen Cassette, Advantage 4th Gen | Technician | E Star 4th Gen owner's p. 41; DIY 4th Gen multi-zone owner's p. 49; DIY 4th Gen cassette owner's p. 55; Advantage 4th Gen service Troubleshooting 5 |
| EL 0C | “System Lacks Refrigerant” What to check Advantage prints “System Lack refrigerant”. The DIY 5th Gen manual lists EL0C with its refrigerant leakage detection codes (DIY 5th Gen Single-Zone Installation & Owner's Manual, p. 11), but the service manual judges it from compressor behavior and from operating changes caused by excessive exhaust temperature, not from a leak sensor (DIY 5th Gen Single-Zone Service Manual, p. 65). The hybrid air handler and Olympus service manuals' engineer-mode lists call EL 0C “Refrigerant leak detected” (DIY Hybrid Air Handler Service Manual, p. 73; Olympus Ducted Air Handler Service Manual, Troubleshooting p. 7). | DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen, DIY 5th Gen Cassette, DIY Hybrid Air Handler, Olympus Ducted | Owner checks, then technician | DIY 5th Gen owner's p. 39; Select owner's p. 41; Easy Pro owner's p. 41; Advantage 5th Gen owner's p. 47; DIY 5th Gen cassette owner's p. 45; Hybrid air handler owner's p. 56; Olympus ducted owner's p. 43 |
| EL 0C | “Refrigerant leak detected.” What to check Operation lamp 8 flashes, timer lamp off. The cassette table says “Refrigerant leakage detection”. The DIY 4th Gen multi-zone table has no EL 0C row; that manual says a detected leak shows as “EC” or “ELOC” or flashing LEDs (DIY 4th Gen Multi-Zone Installation & Owner's Manual, p. 14). | DIY E Star 4th Gen, DIY 4th Gen Cassette, Advantage 4th Gen | Technician | E Star 4th Gen owner's p. 41; DIY 4th Gen cassette owner's p. 55; Advantage 4th Gen service Troubleshooting 5 |
| EL 11 | “Communication malfunction between main unit and secondary units” | DIY 5th Gen Cassette, Olympus Ducted | Owner checks, then technician | DIY 5th Gen cassette owner's p. 45; Olympus ducted owner's p. 43 |
| EL 16 | “Communication malfunction between adapter board and outdoor main board” The outdoor board table says “Communication malfunction between adapter board and ODU main board” (DIY Hybrid Air Handler Installation & Owner's Manual, p. 57). | DIY Hybrid Air Handler | Technician | Hybrid air handler owner's p. 56 |
| EC 07 | “ODU Fan Speed Out of Control” What to check Also in the outdoor board tables (DIY 5th Gen Single-Zone Installation & Owner's Manual, p. 40). Service manual: the outdoor fan speed stays too low or too high for a certain time, the code shows and the system turns off (DIY 5th Gen Single-Zone Service Manual, p. 61). | DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen, DIY 5th Gen Multi-Zone, DIY 5th Gen Cassette, DIY Hybrid Air Handler, Olympus Ducted | Owner checks, then technician | DIY 5th Gen owner's p. 39; Select owner's p. 41; Easy Pro owner's p. 41; Advantage 5th Gen owner's p. 46; DIY 5th Gen multi-zone owner's p. 48; DIY 5th Gen cassette owner's p. 45; Hybrid air handler owner's p. 56; Olympus ducted owner's p. 43 |
| EC 07 | “The outdoor fan speed is operating outside of the normal range.” What to check Operation lamp 12 flashes, timer lamp off. E Star, cassette and Advantage add “(for some models)”. The DIY 4th Gen multi-zone outdoor table says “Outdoor fan speed has been out of control” (DIY 4th Gen Multi-Zone Installation & Owner's Manual, p. 50). | DIY 4th Gen Multi-Zone, DIY E Star 4th Gen, DIY 4th Gen Cassette, Advantage 4th Gen | Technician | DIY 4th Gen multi-zone owner's p. 49; E Star 4th Gen owner's p. 41; DIY 4th Gen cassette owner's p. 56; Advantage 4th Gen service Troubleshooting 5 |
| EC 0D | “ODU malfunction” | DIY Hybrid Air Handler | Technician | Hybrid air handler owner's p. 56 |
| EC 0D | “Outdoor unit malfunction(for some models)” Operation lamp 14 flashes, timer lamp off. | DIY 4th Gen Cassette | Technician | DIY 4th Gen cassette owner's p. 56 |
| EC 50 | “Open or Short Circuit of Outdoor Unit Temperature Sensor (T3, T4, TP)” Outdoor board table. Multi-zone: “ODU Temperature Sensor Error (T3, T4, TP)”; Olympus: “ODU Temp. Sensor error (T3, T4, TP)”. | DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen, DIY 5th Gen Multi-Zone, Olympus Ducted, DIY 4th Gen Multi-Zone | Technician | DIY 5th Gen owner's p. 40; Select owner's p. 42; Easy Pro owner's p. 42; Advantage 5th Gen owner's p. 48; DIY 5th Gen multi-zone owner's p. 48; Olympus ducted owner's p. 44; DIY 4th Gen multi-zone owner's p. 50 |
| EC 51 | “ODU EEPROM Parameter Error” Also in the outdoor board tables. Service manual: the outdoor board's main chip gets no feedback from the EEPROM chip (DIY 5th Gen Single-Zone Service Manual, p. 55). | DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen, DIY 5th Gen Multi-Zone, DIY 5th Gen Cassette, DIY Hybrid Air Handler, Olympus Ducted | Owner checks, then technician | DIY 5th Gen owner's p. 39; Select owner's p. 41; Easy Pro owner's p. 41; Advantage 5th Gen owner's p. 46; DIY 5th Gen multi-zone owner's p. 48; DIY 5th Gen cassette owner's p. 45; Hybrid air handler owner's p. 56; Olympus ducted owner's p. 43 |
| EC 51 | “Outdoor unit EEPROM parameter error.” Operation lamp 5 flashes with the timer lamp off; the cassette table shows the timer lamp on. E Star and Advantage add “(for some models)”. The DIY 4th Gen multi-zone outdoor table says “Outdoor EEPROM malfunction” (DIY 4th Gen Multi-Zone Installation & Owner's Manual, p. 50). | DIY 4th Gen Multi-Zone, DIY 4th Gen Cassette, DIY E Star 4th Gen, Advantage 4th Gen | Technician | DIY 4th Gen multi-zone owner's p. 49; DIY 4th Gen cassette owner's p. 56; E Star 4th Gen owner's p. 41; Advantage 4th Gen service Troubleshooting 5 |
| EC 52 | “ODU Coil Temperature Sensor (T3) Error” Advantage, cassette, hybrid air handler and Olympus: “ODU coil temp. sensor (T3) error”. Also in the outdoor board tables. Service manual: the sensor's sampling voltage is below 0.06 V or above 4.94 V (DIY 5th Gen Single-Zone Service Manual, p. 64). | DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen, DIY 5th Gen Multi-Zone, DIY 5th Gen Cassette, DIY Hybrid Air Handler, Olympus Ducted | Owner checks, then technician | DIY 5th Gen owner's p. 39; Select owner's p. 41; Easy Pro owner's p. 41; Advantage 5th Gen owner's p. 46; DIY 5th Gen multi-zone owner's p. 48; DIY 5th Gen cassette owner's p. 45; Hybrid air handler owner's p. 56; Olympus ducted owner's p. 43 |
| EC 52 | “Condenser coil temperature sensor T3 is in open circuit or has short circuited.” Operation lamp 5 flashes, timer lamp off. | DIY E Star 4th Gen, DIY 4th Gen Multi-Zone, DIY 4th Gen Cassette, Advantage 4th Gen | Technician | E Star 4th Gen owner's p. 41; DIY 4th Gen multi-zone owner's p. 49; DIY 4th Gen cassette owner's p. 56; Advantage 4th Gen service Troubleshooting 5 |
| EC 53 | “ODU Ambient Temperature Sensor (T4) Error” Advantage, cassette, hybrid air handler and Olympus: “ODU ambient temp. sensor (T4) error”; the Advantage outdoor board table prints “(T3)” (Advantage 5th Gen Installation & Owner's Manual, p. 48). Also in the outdoor board tables. | DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen, DIY 5th Gen Multi-Zone, DIY 5th Gen Cassette, DIY Hybrid Air Handler, Olympus Ducted | Owner checks, then technician | DIY 5th Gen owner's p. 39; Select owner's p. 41; Easy Pro owner's p. 41; Advantage 5th Gen owner's p. 46; DIY 5th Gen multi-zone owner's p. 48; DIY 5th Gen cassette owner's p. 45; Hybrid air handler owner's p. 56; Olympus ducted owner's p. 43 |
| EC 53 | “Outdoor room temperature sensor T4 is in open circuit or has short circuited.” Operation lamp 5 flashes, timer lamp off. | DIY E Star 4th Gen, DIY 4th Gen Multi-Zone, DIY 4th Gen Cassette, Advantage 4th Gen | Technician | E Star 4th Gen owner's p. 41; DIY 4th Gen multi-zone owner's p. 49; DIY 4th Gen cassette owner's p. 56; Advantage 4th Gen service Troubleshooting 5 |
| EC 54 | “Comp. Discharge Temperature Sensor (TP) Error” Advantage, cassette, hybrid air handler and Olympus: “COMP. discharge temp. sensor (TP) error”. Also in the outdoor board tables. | DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen, DIY 5th Gen Multi-Zone, DIY 5th Gen Cassette, DIY Hybrid Air Handler, Olympus Ducted | Owner checks, then technician | DIY 5th Gen owner's p. 39; Select owner's p. 41; Easy Pro owner's p. 41; Advantage 5th Gen owner's p. 46; DIY 5th Gen multi-zone owner's p. 48; DIY 5th Gen cassette owner's p. 45; Hybrid air handler owner's p. 56; Olympus ducted owner's p. 43 |
| EC 54 | “Compressor discharge temperature sensor TP is in open circuit or has short circuited.” Operation lamp 5 flashes, timer lamp off. | DIY E Star 4th Gen, DIY 4th Gen Multi-Zone, DIY 4th Gen Cassette, Advantage 4th Gen | Technician | E Star 4th Gen owner's p. 41; DIY 4th Gen multi-zone owner's p. 49; DIY 4th Gen cassette owner's p. 56; Advantage 4th Gen service Troubleshooting 5 |
| EC 55 | “ODU IPM Module Temperature Sensor Malfunction” Outdoor board table in the hybrid air handler and Olympus manuals. | DIY 5th Gen Multi-Zone, DIY Hybrid Air Handler, Olympus Ducted | Technician | DIY 5th Gen multi-zone owner's p. 48; Hybrid air handler owner's p. 57; Olympus ducted owner's p. 44 |
| EC 55 | “IGBT temperature sensor TH is in open circuit or has short circuited” Operation lamp 5 flashes, timer lamp off. | DIY 4th Gen Cassette | Technician | DIY 4th Gen cassette owner's p. 56 |
| EC 56 | “IDU Coil Outlet Temperature Sensor (T2B) Error (Multi-Zone)” The DIY 5th Gen multi-zone table drops “(Multi-Zone)”. Advantage, cassette, hybrid air handler and Olympus write “temp. sensor”. | DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen, DIY 5th Gen Multi-Zone, DIY 5th Gen Cassette, DIY Hybrid Air Handler, Olympus Ducted | Owner checks, then technician | DIY 5th Gen owner's p. 39; Select owner's p. 41; Easy Pro owner's p. 41; Advantage 5th Gen owner's p. 46; DIY 5th Gen multi-zone owner's p. 48; DIY 5th Gen cassette owner's p. 45; Hybrid air handler owner's p. 56; Olympus ducted owner's p. 43 |
| EC 56 | “Evaporator coil outlet temperature sensor T2B is in open circuit or has short circuited(for free-match indoor units)” Operation lamp 5 flashes, timer lamp off. The E Star and multi-zone tables print “shortcircuited” and “short-circuited”. | DIY 4th Gen Cassette, Advantage 4th Gen, DIY E Star 4th Gen, DIY 4th Gen Multi-Zone | Technician | DIY 4th Gen cassette owner's p. 56; Advantage 4th Gen service Troubleshooting 5; E Star 4th Gen owner's p. 41; DIY 4th Gen multi-zone owner's p. 49 |
| EC 57 | “Refrigerant Pipe Temperature Sensor Error” Outdoor board table in the hybrid air handler and Olympus manuals. | DIY 5th Gen Multi-Zone, DIY Hybrid Air Handler, Olympus Ducted | Technician | DIY 5th Gen multi-zone owner's p. 48; Hybrid air handler owner's p. 57; Olympus ducted owner's p. 44 |
| EC 5A | “Failure of Enthalpy Inlet Temperature Sensor” Outdoor board table in the Olympus manual. | DIY 5th Gen Multi-Zone, Olympus Ducted | Technician | DIY 5th Gen multi-zone owner's p. 48; Olympus ducted owner's p. 44 |
| EC 5B | “Failure of Enthalpy Outlet Temperature Sensor” Outdoor board table in the Olympus manual. | DIY 5th Gen Multi-Zone, Olympus Ducted | Technician | DIY 5th Gen multi-zone owner's p. 48; Olympus ducted owner's p. 44 |
| EC 5C | “Pressure Sensor Failure” The seven-segment font of these tables makes it look like “EC SC”. | DIY 5th Gen Multi-Zone, Olympus Ducted | Technician | DIY 5th Gen multi-zone owner's p. 48; Olympus ducted owner's p. 44 |
| EC 5E | “Condenser Temperature Sensor (T3B) Failure” The seven-segment font of these tables makes it look like “EC SE”. | DIY 5th Gen Multi-Zone, Olympus Ducted | Technician | DIY 5th Gen multi-zone owner's p. 48; Olympus ducted owner's p. 44 |
| EC 71 | “Over Current Failure of ODU DC Fan Motor” Outdoor board table. The DIY 5th Gen multi-zone manual says “Overcurrent Failure of Outdoor DC Fan Motor”, the DIY 4th Gen multi-zone manual “Over current failure of outdoor DC fan motor”. | DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen, DIY 5th Gen Multi-Zone, DIY Hybrid Air Handler, Olympus Ducted, DIY 4th Gen Multi-Zone | Technician | DIY 5th Gen owner's p. 40; Select owner's p. 42; Easy Pro owner's p. 42; Advantage 5th Gen owner's p. 48; DIY 5th Gen multi-zone owner's p. 48; Hybrid air handler owner's p. 57; Olympus ducted owner's p. 44; DIY 4th Gen multi-zone owner's p. 50 |
| EC 72 | “Lack Phase Failure of ODU DC Fan Motor” Outdoor board table. The 5th and 4th Gen multi-zone manuals say “Lack Phase Failure of Outdoor DC Fan Motor”. | DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen, DIY 5th Gen Multi-Zone, DIY Hybrid Air Handler, Olympus Ducted, DIY 4th Gen Multi-Zone | Technician | DIY 5th Gen owner's p. 40; Select owner's p. 42; Easy Pro owner's p. 42; Advantage 5th Gen owner's p. 48; DIY 5th Gen multi-zone owner's p. 48; Hybrid air handler owner's p. 57; Olympus ducted owner's p. 44; DIY 4th Gen multi-zone owner's p. 50 |
| EC C1 | “Other IDU Refrigerant Sensor Detects Leakage (Multi-Zone)” Only for units with a refrigerant sensor (DIY 5th Gen Single-Zone Installation & Owner's Manual, p. 11). Advantage and Olympus print it without “(Multi-Zone)”. Not in the DIY Select or Easy Pro owner's manual tables; their service manuals list it. Service manual: on a multi-zone system only the indoor unit that detects the leak keeps sounding its buzzer; the other indoor units show ECC1 without the buzzer (DIY 5th Gen Single-Zone Service Manual, p. 69). | DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen, DIY 5th Gen Cassette, DIY Hybrid Air Handler, Olympus Ducted | Technician | DIY 5th Gen owner's p. 39; Select service p. 42; Easy Pro service p. 42; Advantage 5th Gen owner's p. 46; DIY 5th Gen cassette owner's p. 45; Hybrid air handler owner's p. 56; Olympus ducted owner's p. 43 |
| FH 07 | “Communication malfunction between indoor unit and auto-lifting panel” | DIY 5th Gen Cassette | Owner checks, then technician | DIY 5th Gen cassette owner's p. 45 |
| FH 07 | “Communication malfunction between indoor unit and auto-lifting panel” Operation lamp 15 flashes, timer lamp off. | DIY 4th Gen Cassette | Technician | DIY 4th Gen cassette owner's p. 56 |
| FH CC | “Refrigerant Sensor Error” Not in the DIY Select or Easy Pro owner's manual tables; their service manuals list it. Service manual: the indoor unit receives a fault signal for 10 seconds, or no feedback from the refrigerant sensor for 150 seconds (DIY 5th Gen Single-Zone Service Manual, p. 68). | DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen, DIY 5th Gen Cassette, DIY Hybrid Air Handler, Olympus Ducted | Technician | DIY 5th Gen owner's p. 39; Select service p. 42; Easy Pro service p. 42; Advantage 5th Gen owner's p. 46; DIY 5th Gen cassette owner's p. 45; Hybrid air handler owner's p. 56; Olympus ducted owner's p. 43 |
| FL 09 | “Mismatch between the new and old platforms” | DIY Hybrid Air Handler | Technician | Hybrid air handler owner's p. 56 |
| PC 00 | “ODU IPM Module Protection” The multi-zone table and the hybrid air handler and Olympus outdoor board tables say “IPM Module Protection”. Also in the outdoor board tables. Service manual: the voltage signal the IPM sends to the compressor drive chip is abnormal, the code shows and the system turns off (DIY 5th Gen Single-Zone Service Manual, p. 70). | DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen, DIY 5th Gen Multi-Zone, DIY 5th Gen Cassette, DIY Hybrid Air Handler, Olympus Ducted | Owner checks, then technician | DIY 5th Gen owner's p. 39; Select owner's p. 41; Easy Pro owner's p. 41; Advantage 5th Gen owner's p. 47; DIY 5th Gen multi-zone owner's p. 48; DIY 5th Gen cassette owner's p. 45; Hybrid air handler owner's p. 56; Olympus ducted owner's p. 43 |
| PC 00 | “IPM malfunction or IGBT over-strong current protection.” Operation lamp 7 flashes, timer lamp flashing. The DIY 4th Gen multi-zone outdoor table says “IPM module protection” (DIY 4th Gen Multi-Zone Installation & Owner's Manual, p. 50), and its guide's description of this fault begins “PC 00/(ODU)P6:” (DIY 4th Gen Multi-Zone Troubleshooting & Solutions Guide, Troubleshooting p. 36). The DIY E Star 3rd Gen table prints the same wording as P0. | DIY E Star 4th Gen, DIY 4th Gen Multi-Zone, DIY 4th Gen Cassette, Advantage 4th Gen | Technician | E Star 4th Gen owner's p. 41; DIY 4th Gen multi-zone owner's p. 49; DIY 4th Gen cassette owner's p. 56; Advantage 4th Gen service Troubleshooting 5 |
| PC 01 | “ODU Voltage Protection” Service manual: an abnormal rise or drop in voltage is detected by the voltage detection circuit (DIY 5th Gen Single-Zone Service Manual, p. 71). | DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen, DIY 5th Gen Cassette, DIY Hybrid Air Handler, Olympus Ducted | Owner checks, then technician | DIY 5th Gen owner's p. 39; Select owner's p. 41; Easy Pro owner's p. 41; Advantage 5th Gen owner's p. 47; DIY 5th Gen cassette owner's p. 45; Hybrid air handler owner's p. 56; Olympus ducted owner's p. 43 |
| PC 01 | “Over voltage or over low voltage protection.” Operation lamp 2 flashes, timer lamp flashing. The DIY E Star 3rd Gen table prints the same wording as P1. | DIY E Star 4th Gen, DIY 4th Gen Multi-Zone, DIY 4th Gen Cassette, Advantage 4th Gen | Technician | E Star 4th Gen owner's p. 41; DIY 4th Gen multi-zone owner's p. 49; DIY 4th Gen cassette owner's p. 56; Advantage 4th Gen service Troubleshooting 5 |
| PC 02 | “Compressor Top (or IPM) Temperature Protection” Advantage, cassette, hybrid air handler and Olympus indoor tables: “Compressor top (or IPM) temp. protection”. The hybrid air handler's outdoor board table adds “/ Refrigerant sensor error” (DIY Hybrid Air Handler Installation & Owner's Manual, p. 57). Also in the outdoor board tables. DIY 5th Gen service manual: the IPM module temperature is higher than a certain value (DIY 5th Gen Single-Zone Service Manual, p. 72). | DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen, DIY 5th Gen Multi-Zone, DIY 5th Gen Cassette, DIY Hybrid Air Handler, Olympus Ducted | Owner checks, then technician | DIY 5th Gen owner's p. 39; Select owner's p. 41; Easy Pro owner's p. 41; Advantage 5th Gen owner's p. 47; DIY 5th Gen multi-zone owner's p. 48; DIY 5th Gen cassette owner's p. 45; Hybrid air handler owner's p. 56; Olympus ducted owner's p. 43 |
| PC 02 | “High temperature protection of IPM module or high pressure protection (forsome models).” Operation lamp 3 flashes, timer lamp flashing. DIY 4th Gen multi-zone: “High temperature protection of IPM module/compressor, or high pressure protection.”; its outdoor table says “Top temperature protection of compressor” (DIY 4th Gen Multi-Zone Installation & Owner's Manual, p. 50), and its guide “Top temperature protection of compressor or High temperature protection of IPM module or High pressure protection” (DIY 4th Gen Multi-Zone Troubleshooting & Solutions Guide, Troubleshooting p. 4). Advantage: no “(for some models)”. The E Star section says that on some models with a high pressure switch, the switch cuts off the system above 4.4 MPa (DIY E Star 4th Gen Installation & Owner's Manual, p. 53). | DIY E Star 4th Gen, DIY 4th Gen Multi-Zone, Advantage 4th Gen | Technician | E Star 4th Gen owner's p. 41; DIY 4th Gen multi-zone owner's p. 49; Advantage 4th Gen service Troubleshooting 5 |
| PC 02 | “Top temperature protection of compressor or High temperature protection of IPM module” Operation lamp 3 flashes, timer lamp flashing. Unlike the other 4th Gen tables, no high pressure protection in the wording. | DIY 4th Gen Cassette | Technician | DIY 4th Gen cassette owner's p. 56 |
| PC 03 | “Pressure Protection (low or high pressure)” What to check Advantage, cassette and Olympus add “(for some models)”. The outdoor board tables show high and low pressure separately as PC 30 and PC 31; the DIY 5th Gen multi-zone table has those two and no PC 03. Service manual: the outdoor pressure switch cuts off the system above 638 PSI (4.4 MPa) or below 18.85 PSI (0.13 MPa) (DIY 5th Gen Single-Zone Service Manual, p. 74). | DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen, DIY 5th Gen Cassette, DIY Hybrid Air Handler, Olympus Ducted | Owner checks, then technician | DIY 5th Gen owner's p. 39; Select owner's p. 41; Easy Pro owner's p. 41; Advantage 5th Gen owner's p. 47; DIY 5th Gen cassette owner's p. 45; Hybrid air handler owner's p. 56; Olympus ducted owner's p. 43 |
| PC 03 | “High pressure protection or low pressure protection.” What to check Operation lamp 7 flashes, timer lamp flashing. Cassette and Advantage add “(for some models)”. The Advantage service manual's letter-code table lists this fault as P6 (Advantage 4th Gen Service Manual, Troubleshooting p. 4). | DIY 4th Gen Multi-Zone, DIY 4th Gen Cassette, Advantage 4th Gen | Technician | DIY 4th Gen multi-zone owner's p. 49; DIY 4th Gen cassette owner's p. 56; Advantage 4th Gen service Troubleshooting 5 |
| PC 03 | “Low pressure protection (for some models).” What to check Operation lamp 7 flashes, timer lamp flashing. Section 10.11: the outdoor pressure switch cuts off the system when pressure falls below 0.13 MPa (DIY E Star 4th Gen Installation & Owner's Manual, p. 55). | DIY E Star 4th Gen | Technician | E Star 4th Gen owner's p. 41 |
| PC 04 | “Inverter Compressor Drive Error” What to check The DIY Select and Easy Pro owner's manuals call PC 04 “Compressor Feedback Protection” (DIY Select Installation & Owner's Manual, p. 41; Easy Pro Installation & Owner's Manual, p. 41); their service manuals use the wording above, and both point to section TS12-S. Service manual: an abnormal compressor drive is found by a detection circuit that checks the communication signal, the voltage and the compressor rotation speed signal (DIY 5th Gen Single-Zone Service Manual, p. 73). | DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen, DIY 5th Gen Cassette, DIY Hybrid Air Handler, Olympus Ducted | Owner checks, then technician | DIY 5th Gen owner's p. 39; Select service p. 42; Easy Pro service p. 42; Advantage 5th Gen owner's p. 47; DIY 5th Gen cassette owner's p. 45; Hybrid air handler owner's p. 56; Olympus ducted owner's p. 43 |
| PC 04 | “Inverter compressor drive error.” What to check Operation lamp 5 flashes, timer lamp flashing. The DIY E Star 3rd Gen table prints the same wording as P4. | DIY E Star 4th Gen, DIY 4th Gen Multi-Zone, DIY 4th Gen Cassette, Advantage 4th Gen | Technician | E Star 4th Gen owner's p. 41; DIY 4th Gen multi-zone owner's p. 49; DIY 4th Gen cassette owner's p. 56; Advantage 4th Gen service Troubleshooting 5 |
| PC 06 | “Discharge Temperature Protection of Compressor” Outdoor board table. The DIY 4th Gen multi-zone manual says “Temperature protection of compressor discharge”. | DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen, DIY 5th Gen Multi-Zone, DIY Hybrid Air Handler, Olympus Ducted, DIY 4th Gen Multi-Zone | Technician | DIY 5th Gen owner's p. 40; Select owner's p. 42; Easy Pro owner's p. 42; Advantage 5th Gen owner's p. 48; DIY 5th Gen multi-zone owner's p. 48; Hybrid air handler owner's p. 57; Olympus ducted owner's p. 44; DIY 4th Gen multi-zone owner's p. 50 |
| PC 08 | “ODU Overcurrent Protection” Outdoor board table. Multi-zone and hybrid air handler: “Outdoor Overcurrent Protection”. | DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen, DIY 5th Gen Multi-Zone, DIY Hybrid Air Handler, Olympus Ducted | Technician | DIY 5th Gen owner's p. 40; Select owner's p. 42; Easy Pro owner's p. 42; Advantage 5th Gen owner's p. 48; DIY 5th Gen multi-zone owner's p. 48; Hybrid air handler owner's p. 57; Olympus ducted owner's p. 44 |
| PC 08 | “Current overload protection.” Operation lamp 1 flash, timer lamp flashing. E Star and Advantage add “(for some models)”. The DIY 4th Gen multi-zone outdoor table says “Outdoor overcurrent protection” (DIY 4th Gen Multi-Zone Installation & Owner's Manual, p. 50). | DIY 4th Gen Multi-Zone, DIY E Star 4th Gen, Advantage 4th Gen | Technician | DIY 4th Gen multi-zone owner's p. 49; E Star 4th Gen owner's p. 41; Advantage 4th Gen service Troubleshooting 5 |
| PC 0A | “High Temperature Protection of Condenser” Outdoor board table. The DIY 5th Gen single-zone and Olympus tables misspell it “High Temperatue Protection of Condenser”. | DIY Select, Easy Pro, Advantage 5th Gen, DIY 5th Gen Multi-Zone, DIY Hybrid Air Handler, DIY 5th Gen, Olympus Ducted, DIY 4th Gen Multi-Zone | Technician | Select owner's p. 42; Easy Pro owner's p. 42; Advantage 5th Gen owner's p. 48; DIY 5th Gen multi-zone owner's p. 48; Hybrid air handler owner's p. 57; DIY 5th Gen owner's p. 40; Olympus ducted owner's p. 44; DIY 4th Gen multi-zone owner's p. 50 |
| PC 0F | “PFC Module Protection” Outdoor board table. | DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen, DIY 5th Gen Multi-Zone, DIY Hybrid Air Handler, Olympus Ducted, DIY 4th Gen Multi-Zone | Technician | DIY 5th Gen owner's p. 40; Select owner's p. 42; Easy Pro owner's p. 42; Advantage 5th Gen owner's p. 48; DIY 5th Gen multi-zone owner's p. 48; Hybrid air handler owner's p. 57; Olympus ducted owner's p. 44; DIY 4th Gen multi-zone owner's p. 50 |
| PC 0L | “Low Ambient Temperature Protection” Advantage's indoor table prints “Low ambient temperature (for some models)” and its outdoor board table “Low ambient temperature protection (for some models)”; the cassette adds “(for some models)”. The manual says certain safety protection features may activate and disable the unit outside its operating temperature ranges; for the DIY 5th Gen single-zone those are −13°F to 122°F (−25°C to 50°C) outdoors in cooling and −13°F to 75°F (−25°C to 24°C) in heating (DIY 5th Gen Single-Zone Installation & Owner's Manual, p. 13). | DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen, DIY 5th Gen Multi-Zone, DIY 5th Gen Cassette, DIY Hybrid Air Handler, Olympus Ducted | Owner checks, then technician | DIY 5th Gen owner's p. 39; Select owner's p. 41; Easy Pro owner's p. 41; Advantage 5th Gen owner's p. 47; DIY 5th Gen multi-zone owner's p. 48; DIY 5th Gen cassette owner's p. 45; Hybrid air handler owner's p. 56; Olympus ducted owner's p. 43 |
| PC 0L | “Low ambient temperature protection” In the DIY 4th Gen multi-zone outdoor table. The cassette table adds “(for some models)” with operation lamp 4 flashes and the timer lamp flashing. | DIY 4th Gen Multi-Zone, DIY 4th Gen Cassette | Technician | DIY 4th Gen multi-zone owner's p. 50; DIY 4th Gen cassette owner's p. 56 |
| PC 10 | “ODU Low AC Voltage Protection” Outdoor board table. | DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen, DIY 5th Gen Multi-Zone, DIY Hybrid Air Handler, Olympus Ducted | Technician | DIY 5th Gen owner's p. 40; Select owner's p. 42; Easy Pro owner's p. 42; Advantage 5th Gen owner's p. 48; DIY 5th Gen multi-zone owner's p. 48; Hybrid air handler owner's p. 57; Olympus ducted owner's p. 44 |
| PC 10 | “Outdoor unit low AC voltage protection” Outdoor unit table. | DIY 4th Gen Multi-Zone | Technician | DIY 4th Gen multi-zone owner's p. 50 |
| PC 11 | “ODU Main Control Board DC Bus High Voltage Protection” Outdoor board table. | DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen, DIY 5th Gen Multi-Zone, DIY Hybrid Air Handler, Olympus Ducted | Technician | DIY 5th Gen owner's p. 40; Select owner's p. 42; Easy Pro owner's p. 42; Advantage 5th Gen owner's p. 48; DIY 5th Gen multi-zone owner's p. 48; Hybrid air handler owner's p. 57; Olympus ducted owner's p. 44 |
| PC 11 | “Outdoor unit main control board DC bus high voltage protection” Outdoor unit table. | DIY 4th Gen Multi-Zone | Technician | DIY 4th Gen multi-zone owner's p. 50 |
| PC 12 | “ODU Main Control Board DC Bus Low Voltage Protection/341 MCE Error” Outdoor board table. | DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen, DIY 5th Gen Multi-Zone, DIY Hybrid Air Handler, Olympus Ducted | Technician | DIY 5th Gen owner's p. 40; Select owner's p. 42; Easy Pro owner's p. 42; Advantage 5th Gen owner's p. 48; DIY 5th Gen multi-zone owner's p. 48; Hybrid air handler owner's p. 57; Olympus ducted owner's p. 44 |
| PC 12 | “Outdoor unit main control board DC bus high voltage protection /341 MCE error” Outdoor unit table. Printed “high voltage”, the same words as its PC 11 line; the 5th Gen tables say low voltage for PC 12. | DIY 4th Gen Multi-Zone | Technician | DIY 4th Gen multi-zone owner's p. 50 |
| PC 13 | “The AC Power is Cut Off or the AC Voltage Detection Circuit Fails” Outdoor board table in the Olympus manual. | DIY 5th Gen Multi-Zone, Olympus Ducted | Technician | DIY 5th Gen multi-zone owner's p. 48; Olympus ducted owner's p. 44 |
| PC 30 | “System High Pressure Protection” Outdoor board table. The DIY 4th Gen multi-zone manual says “High pressure protection”. The single-zone service manual sends PC 03, PC 30 and PC 31 to the same section, TS26-INV (DIY 5th Gen Single-Zone Service Manual, pp. 36–37); the multi-zone service manual says the outdoor pressure switch cuts off the system above 638 PSI (4.4 MPa) (DIY 5th Gen Multi-Zone Service Manual, p. 61). | DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen, DIY 5th Gen Multi-Zone, DIY Hybrid Air Handler, Olympus Ducted, DIY 4th Gen Multi-Zone | Technician | DIY 5th Gen owner's p. 40; Select owner's p. 42; Easy Pro owner's p. 42; Advantage 5th Gen owner's p. 48; DIY 5th Gen multi-zone owner's p. 48; Hybrid air handler owner's p. 57; Olympus ducted owner's p. 44; DIY 4th Gen multi-zone owner's p. 50 |
| PC 31 | “System Low Pressure Protection” Outdoor board table. The DIY 4th Gen multi-zone manual says “Low pressure protection”. The multi-zone service manual says the outdoor pressure switch cuts off the system below 18.85 PSI (0.13 MPa) (DIY 5th Gen Multi-Zone Service Manual, p. 62). | DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen, DIY 5th Gen Multi-Zone, DIY Hybrid Air Handler, Olympus Ducted, DIY 4th Gen Multi-Zone | Technician | DIY 5th Gen owner's p. 40; Select owner's p. 42; Easy Pro owner's p. 42; Advantage 5th Gen owner's p. 48; DIY 5th Gen multi-zone owner's p. 48; Hybrid air handler owner's p. 57; Olympus ducted owner's p. 44; DIY 4th Gen multi-zone owner's p. 50 |
| PC 40 | “Communication Error between Outdoor Main Chip & Compressor-Driven Chip” Outdoor board table. Multi-zone and hybrid air handler: “Communication Error between ODU Main Chip & Compressor Driven Chip”. | DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen, DIY 5th Gen Multi-Zone, DIY Hybrid Air Handler, Olympus Ducted | Technician | DIY 5th Gen owner's p. 40; Select owner's p. 42; Easy Pro owner's p. 42; Advantage 5th Gen owner's p. 48; DIY 5th Gen multi-zone owner's p. 48; Hybrid air handler owner's p. 57; Olympus ducted owner's p. 44 |
| PC 40 | “Communication malfunction between IPM board and outdoor main board” Outdoor unit table. | DIY 4th Gen Multi-Zone | Technician | DIY 4th Gen multi-zone owner's p. 50 |
| PC 41 | “Compressor current sampling failure” Outdoor board table. | DIY Hybrid Air Handler | Technician | Hybrid air handler owner's p. 57 |
| PC 42 | “Compressor start failure of outdoor unit” Outdoor board table. | DIY Hybrid Air Handler | Technician | Hybrid air handler owner's p. 57 |
| PC 43 | “ODU Compressor Lack Phase Protection” Outdoor board table. The DIY 4th Gen multi-zone manual says “Outdoor compressor lack phase protection”. | DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen, DIY 5th Gen Multi-Zone, DIY Hybrid Air Handler, Olympus Ducted, DIY 4th Gen Multi-Zone | Technician | DIY 5th Gen owner's p. 40; Select owner's p. 42; Easy Pro owner's p. 42; Advantage 5th Gen owner's p. 48; DIY 5th Gen multi-zone owner's p. 48; Hybrid air handler owner's p. 57; Olympus ducted owner's p. 44; DIY 4th Gen multi-zone owner's p. 50 |
| PC 44 | “ODU Zero Speed Protection” Outdoor board table. The DIY 4th Gen multi-zone manual says “Outdoor unit zero speed protection”. | DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen, DIY 5th Gen Multi-Zone, DIY Hybrid Air Handler, Olympus Ducted, DIY 4th Gen Multi-Zone | Technician | DIY 5th Gen owner's p. 40; Select owner's p. 42; Easy Pro owner's p. 42; Advantage 5th Gen owner's p. 48; DIY 5th Gen multi-zone owner's p. 48; Hybrid air handler owner's p. 57; Olympus ducted owner's p. 44; DIY 4th Gen multi-zone owner's p. 50 |
| PC 45 | “ODU IR Chip Drive Failure” Outdoor board table. The DIY 4th Gen multi-zone manual says “Outdoor unit IR chip drive failure”. | DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen, DIY 5th Gen Multi-Zone, DIY Hybrid Air Handler, Olympus Ducted, DIY 4th Gen Multi-Zone | Technician | DIY 5th Gen owner's p. 40; Select owner's p. 42; Easy Pro owner's p. 42; Advantage 5th Gen owner's p. 48; DIY 5th Gen multi-zone owner's p. 48; Hybrid air handler owner's p. 57; Olympus ducted owner's p. 44; DIY 4th Gen multi-zone owner's p. 50 |
| PC 46 | “Compressor Speed Out of Control” Outdoor board table. Advantage and the multi-zone manuals say “Compressor speed has been out of control”. | DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen, DIY 5th Gen Multi-Zone, DIY Hybrid Air Handler, Olympus Ducted, DIY 4th Gen Multi-Zone | Technician | DIY 5th Gen owner's p. 40; Select owner's p. 42; Easy Pro owner's p. 42; Advantage 5th Gen owner's p. 48; DIY 5th Gen multi-zone owner's p. 48; Hybrid air handler owner's p. 57; Olympus ducted owner's p. 44; DIY 4th Gen multi-zone owner's p. 50 |
| PC 49 | “Compressor Overcurrent Failure” Outdoor board table. | DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen, DIY 5th Gen Multi-Zone, DIY Hybrid Air Handler, Olympus Ducted, DIY 4th Gen Multi-Zone | Technician | DIY 5th Gen owner's p. 40; Select owner's p. 42; Easy Pro owner's p. 42; Advantage 5th Gen owner's p. 48; DIY 5th Gen multi-zone owner's p. 48; Hybrid air handler owner's p. 57; Olympus ducted owner's p. 44; DIY 4th Gen multi-zone owner's p. 50 |
| PC A1 | “Condensation Protection of Refrigerant Pipe” The seven-segment font of these tables makes it look like “PC AI”. | DIY 5th Gen Multi-Zone, Olympus Ducted | Technician | DIY 5th Gen multi-zone owner's p. 48; Olympus ducted owner's p. 44 |
| PH 90 | “High Temperature Protection of Evaporator” Outdoor board table. The DIY 5th Gen service manual's engineer-mode list prints PH 90 as “Low temperature protection of evaporator” (DIY 5th Gen Single-Zone Service Manual, p. 44). | DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen, DIY Hybrid Air Handler | Technician | DIY 5th Gen owner's p. 40; Select owner's p. 42; Easy Pro owner's p. 42; Advantage 5th Gen owner's p. 48; Hybrid air handler owner's p. 57 |
| PH 91 | “Low Temperature Protection of Evaporator” Outdoor board table. | DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen, DIY Hybrid Air Handler | Technician | DIY 5th Gen owner's p. 40; Select owner's p. 42; Easy Pro owner's p. 42; Advantage 5th Gen owner's p. 48; Hybrid air handler owner's p. 57 |
| LC 06 | “High Temperature Protection of Inverter Module (IPM)” Outdoor board table. | DIY 5th Gen, DIY Select, Easy Pro, Advantage 5th Gen, DIY 5th Gen Multi-Zone, DIY Hybrid Air Handler, Olympus Ducted | Technician | DIY 5th Gen owner's p. 40; Select owner's p. 42; Easy Pro owner's p. 42; Advantage 5th Gen owner's p. 48; DIY 5th Gen multi-zone owner's p. 48; Hybrid air handler owner's p. 57; Olympus ducted owner's p. 44 |
| LC 06 | “IPM module frequency limit shutdown/IPM high temperature protection” Outdoor unit table. | DIY 4th Gen Multi-Zone | Technician | DIY 4th Gen multi-zone owner's p. 50 |
| E0 | “Indoor unit EEPROM parameter error” Operation LED 1 flash, timer LED off. Later DIY manuals print this fault as EH 00. | DIY E Star 3rd Gen | Owner checks, then technician | E Star 3rd Gen owner's p. 39 |
| E1 | “Indoor / outdoor units communication error **” What to check Operation LED 2 flashes, timer LED off. The ** note says the wire colors of this series may differ from previous models, other series and general conventions, and that all wiring must follow the wiring diagrams in Section 7. Later DIY manuals use EL 01 for a communication error between the units. Letter codes are not shared safely across documents: the Advantage 4th Gen service manual's letter table also has E1 as an indoor/outdoor communication error (Advantage 4th Gen Service Manual, Troubleshooting p. 4), but other letters such as P6 change meaning. | DIY E Star 3rd Gen | Owner checks, then technician | E Star 3rd Gen owner's p. 39 |
| E2 | “Zero-crossing signal detection error” Operation LED 3 flashes, timer LED off. | DIY E Star 3rd Gen | Owner checks, then technician | E Star 3rd Gen owner's p. 39 |
| E3/E88 | “Indoor fan speed has been out of control” Printed “E3/E88”. Operation LED 4 flashes, timer LED off. In other MrCool manuals “88” is only the label of a flash-timing diagram, not a code (Advantage 5th Gen Installation & Owner's Manual, p. 47). | DIY E Star 3rd Gen | Owner checks, then technician | E Star 3rd Gen owner's p. 39 |
| E4 | “Indoor room temperature sensor T1 open circuit or short circuit” Operation LED 5 flashes, timer LED off. Not the same E4 everywhere: the contents of the DIY 4th Gen multi-zone guide pair “(ODU)E4” with EC 50, an outdoor temperature sensor code (DIY 4th Gen Multi-Zone Troubleshooting & Solutions Guide, contents, section 8.4). | DIY E Star 3rd Gen | Owner checks, then technician | E Star 3rd Gen owner's p. 39 |
| E5 | “Evaporator coil temperature sensor T2 open circuit or short circuit” Operation LED 6 flashes, timer LED off. Not the same E5 everywhere: the DIY 4th Gen multi-zone guide heads a section “PC 01 / E5 (Over voltage or too low voltage protection)” (DIY 4th Gen Multi-Zone Troubleshooting & Solutions Guide, Troubleshooting p. 38). | DIY E Star 3rd Gen | Owner checks, then technician | E Star 3rd Gen owner's p. 39 |
| EC | “Refrigerant leakage detection” Operation LED 7 flashes, timer LED off. The manual says that when refrigerant leakage is detected the indoor unit displays “EC” or “ELOC” or flashes LEDs (DIY E Star 3rd Gen Installation & Owner's Manual, p. 12). | DIY E Star 3rd Gen | Owner checks, then technician | E Star 3rd Gen owner's p. 39 |
| F1 | “Outdoor ambient temperature sensor T4 open circuit or short circuit” Operation LED 2 flashes, timer LED on. | DIY E Star 3rd Gen | Owner checks, then technician | E Star 3rd Gen owner's p. 39 |
| F2 | “Condenser coil temperature sensor T3 open circuit or short circuit” Operation LED 3 flashes, timer LED on. | DIY E Star 3rd Gen | Owner checks, then technician | E Star 3rd Gen owner's p. 39 |
| F3 | “Compressor discharge temperature sensor T5 open circuit or short circuit” Operation LED 4 flashes, timer LED on. The same table also lists P6 “Discharge temp sensor” without explaining the difference. The Advantage 4th Gen service manual names this sensor TP (Advantage 4th Gen Service Manual, Troubleshooting p. 4). | DIY E Star 3rd Gen | Owner checks, then technician | E Star 3rd Gen owner's p. 39 |
| F4 | “Outdoor unit EEPROM parameter error” Operation LED 5 flashes, timer LED on. | DIY E Star 3rd Gen | Owner checks, then technician | E Star 3rd Gen owner's p. 39 |
| F5 | “Outdoor fan speed has been out of control” Operation LED 6 flashes, timer LED on. | DIY E Star 3rd Gen | Owner checks, then technician | E Star 3rd Gen owner's p. 39 |
| P0 | “IPM malfunction or IGBT over-strong current protection” Operation LED 1 flash, timer LED flashing. The 4th Gen DIY manuals print this wording as PC 00. Not the same P0 everywhere: the contents of the DIY 4th Gen multi-zone guide list “PC 02/(ODU)P0 (Top temperature protection of compressor …)” (DIY 4th Gen Multi-Zone Troubleshooting & Solutions Guide, contents, section 8.13). | DIY E Star 3rd Gen | Owner checks, then technician | E Star 3rd Gen owner's p. 39 |
| P1 | “Over voltage or over low voltage protection” Operation LED 2 flashes, timer LED flashing. The 4th Gen DIY manuals print this wording as PC 01. | DIY E Star 3rd Gen | Owner checks, then technician | E Star 3rd Gen owner's p. 39 |
| P2 | “High temperature protection of compressor top diagnosis and solution (only for 9k,12k models)” Operation LED 3 flashes, timer LED flashing. Printed as shown, including “diagnosis and solution”. In the Advantage 4th Gen service manual's letter table P2 is “High temperature protection of IPM module or High pressure protection” (Advantage 4th Gen Service Manual, Troubleshooting p. 4). | DIY E Star 3rd Gen | Owner checks, then technician | E Star 3rd Gen owner's p. 39 |
| P4 | “Inverter compressor drive error” What to check Operation LED 5 flashes, timer LED flashing. The 4th and 5th Gen DIY manuals use PC 04 for this wording. The Advantage 4th Gen service manual's letter table also has P4 with this meaning (Advantage 4th Gen Service Manual, Troubleshooting p. 4). | DIY E Star 3rd Gen | Owner checks, then technician | E Star 3rd Gen owner's p. 39 |
| P6 | “Discharge temp sensor” What to check No LED pattern printed for this row. P6 means other things in other MrCool documents: “High pressure protection or low pressure protection(for some models)” in the Advantage 4th Gen service manual's letter table (Advantage 4th Gen Service Manual, Troubleshooting p. 4), and in the DIY 4th Gen multi-zone guide the description of PC 00, IPM malfunction, begins “PC 00/(ODU)P6” (DIY 4th Gen Multi-Zone Troubleshooting & Solutions Guide, Troubleshooting p. 36). | DIY E Star 3rd Gen | Owner checks, then technician | E Star 3rd Gen owner's p. 39 |
| P7 | “USB Smart Controller module not installed” No LED pattern printed for this row. | DIY E Star 3rd Gen | Owner checks, then technician | E Star 3rd Gen owner's p. 39 |
How to read a MrCool code
Find your series before you read a meaning. MrCool manuals use three code styles, and a code can mean one thing in one generation and something else in another. The E Star manuals and the current DIY single-zone manual print a Version Date but no generation number (the 4th Gen multi-zone manual’s cover does say “4th Generation”). MrCool’s file names number the generations (mc-diy-3, mc-diy-4, mc-diy-5 in the links under Sources), and the model numbers tell them apart: the 3rd Gen E Star manual lists outdoor units such as DIY-24-HP-C-230B DIY E Star 3rd Gen Installation & Owner’s Manual, p. 21, the 4th Gen E Star manual units ending in -115C and -230C DIY E Star 4th Gen Installation & Owner’s Manual, p. 22, and the current DIY manual models ending in D25-O (DIY 5th Gen Single-Zone Installation & Owner’s Manual, cover).
- 5th Gen DIY and the current DIY Select, Easy Pro, Advantage, cassette, multi-zone, hybrid air handler and Olympus ducted manuals: the indoor display shows two letters and two characters, such as EH 00 or PC 03 DIY 5th Gen Single-Zone Installation & Owner’s Manual, p. 39. A second table lists the codes of the digital display on the outdoor unit’s auxiliary board DIY 5th Gen Single-Zone Installation & Owner’s Manual, p. 40. The owner’s manuals do not say how to read that board; the service manual describes its digital display and the SW1 check switch on it DIY 5th Gen Single-Zone Service Manual, p. 38. On the hybrid air handler, the wired control’s LED flashes the active fault code DIY Hybrid Air Handler Installation & Owner’s Manual, p. 45.
- 4th Gen (E Star, multi-zone, cassette, Advantage): the operation lamp flashes a set number of times, the timer lamp may turn on or flash, and the display shows a code from the same EH, EL, EC and PC groups DIY E Star 4th Gen Installation & Owner’s Manual, p. 41. The table gives the flash count for each code.
- 3rd Gen DIY E Star: mostly one letter and one digit, from E0 to P7, plus EC and E3/E88, with operation and timer LED patterns DIY E Star 3rd Gen Installation & Owner’s Manual, p. 39.
Letter codes are where generations disagree most. P6 is “Discharge temp sensor” in the 3rd Gen E Star table DIY E Star 3rd Gen Installation & Owner’s Manual, p. 39, but high or low pressure protection in the Advantage 4th Gen service manual’s letter table Advantage 4th Gen Service Manual, Troubleshooting p. 4. Each row of the table names the series its meaning comes from.
Not everything on the display is a code. The manuals say: “The display board may show a garbled code or a code undefined by the service manual. Ensure that this code is not a temperature reading.” DIY 5th Gen Single-Zone Installation & Owner’s Manual, p. 39. Codes people search for, such as FA, H3, H6, H7 and RP, are not printed as error codes in any MrCool manual used here. Apart from the 3rd Gen E Star code “E3/E88” DIY E Star 3rd Gen Installation & Owner’s Manual, p. 39, “88” appears only as the label of a flash-timing diagram Advantage 5th Gen Installation & Owner’s Manual, p. 47.
The table quotes the error tables of the installation and owner’s manuals. For Advantage 4th Gen it uses the service manual, the only MrCool document with a code table for that series. The service manuals also print an “Error Code of Engineer Mode” list, and the 4th Gen cassette manual a “Display / Error Information” list, with status codes such as NA, LC 01 and LH 00 DIY 5th Gen Single-Zone Service Manual, pp. 43–44; DIY 4th Gen Cassette Installation & Owner’s Manual, pp. 57–58. Codes found only in those lists are left out.
Display modes in the code tables
Some rows in the code tables name a mode or a reminder: DF is defrost, CL is Active Clean (on Advantage and the 4th Gen multi-zone also the filter cleaning reminder), nF is the filter replacement reminder, FP is the 46°F (8°C) heating feature, FC is forced cooling, AP is the Wi-Fi setup mode and CP is “Remote Switched Off”.
Whether a table marks them as normal depends on the manual. These tables print “Normal Display, not error code” (or “not an error code”) next to them:
- DIY Select and Easy Pro, both tables DIY Select Installation & Owner’s Manual, pp. 41–42; Easy Pro Installation & Owner’s Manual, pp. 41–42;
- Advantage 5th Gen, both tables Advantage 5th Gen Installation & Owner’s Manual, pp. 46, 48;
- DIY 5th Gen multi-zone DIY 5th Gen Multi-Zone Installation & Owner’s Manual, p. 48;
- the outdoor board tables of the hybrid air handler and Olympus, for DF and FC DIY Hybrid Air Handler Installation & Owner’s Manual, p. 57; Olympus Ducted Air Handler Installation & Owner’s Manual, p. 44;
- DIY 4th Gen multi-zone DIY 4th Gen Multi-Zone Installation & Owner’s Manual, p. 50; DIY 4th Gen Multi-Zone Troubleshooting & Solutions Guide, Troubleshooting pp. 4, 6.
The DIY 5th Gen single-zone manual lists them among the error codes with no such mark in either table DIY 5th Gen Single-Zone Installation & Owner’s Manual, pp. 39–40. The cassette and Olympus indoor display tables mark only FC, “Not an error code” DIY 5th Gen Cassette Installation & Owner’s Manual, p. 45; Olympus Ducted Air Handler Installation & Owner’s Manual, p. 43.
“–” (printed “––”) is a mode conflict on a multi-zone system: if one indoor unit selects heat mode, the other running units stop and show “–” DIY 5th Gen Multi-Zone Installation & Owner’s Manual, p. 43.
Clearing a code
No MrCool owner’s manual gives a reset for a particular code. The Solution column of the code tables points to TS sections of the service manual, which are written for technicians. What the owner’s manuals give is one procedure for any code:
“The unit may stop operation or continue to run safely. If the indicator lamps continue to flash or error codes appear, wait for about 10 minutes. The problem may resolve itself. If not, disconnect the power, then connect it again. Turn the unit on. If the problem persists, disconnect the power and contact MRCOOL®.” DIY 5th Gen Single-Zone Installation & Owner’s Manual, p. 38
The DIY Select, Easy Pro, cassette and Olympus manuals print the same text DIY Select Installation & Owner’s Manual, p. 40; Easy Pro Installation & Owner’s Manual, p. 40; DIY 5th Gen Cassette Installation & Owner’s Manual, p. 44; Olympus Ducted Air Handler Installation & Owner’s Manual, p. 41, and Advantage 5th Gen ends it with MrCool customer service Advantage 5th Gen Installation & Owner’s Manual, p. 45. The 4th Gen E Star and multi-zone manuals say “roughly 10 minutes” and add: “DO NOT attempt these repairs yourself, as doing this could cause personal injury, damage to your unit, and/or void the warranty.” DIY E Star 4th Gen Installation & Owner’s Manual, p. 41. The 3rd Gen E Star manual gives the same wait and power cycle DIY E Star 3rd Gen Installation & Owner’s Manual, p. 38. The 5th Gen multi-zone, hybrid air handler and 4th Gen cassette manuals print no wait-and-restart step. The first two say to contact a local dealer or MrCool customer service DIY 5th Gen Multi-Zone Installation & Owner’s Manual, p. 46; DIY Hybrid Air Handler Installation & Owner’s Manual, p. 54, the cassette manual a local dealer or the nearest customer service center DIY 4th Gen Cassette Installation & Owner’s Manual, p. 53.
After power comes back, a buzz means the unit powered on normally, and it restarts with its prior settings DIY 5th Gen Single-Zone Installation & Owner’s Manual, p. 11. It cannot be restarted within 3 minutes of being turned off DIY 5th Gen Single-Zone Installation & Owner’s Manual, p. 37.
A code that comes back after the restart is not cleared. The manual’s next step is to disconnect the power and contact MrCool with your model number and a description of what the unit did DIY 5th Gen Single-Zone Installation & Owner’s Manual, pp. 37–38. It gives MrCool tech support as (270) 366-0457 DIY 5th Gen Single-Zone Installation & Owner’s Manual, p. 3.
When to stop and call a professional
Turn the unit off immediately if a wire is damaged or abnormally warm, you smell burning, the unit makes loud or abnormal sounds, a fuse blows or the breaker trips frequently, or water or objects fall into or out of the unit. The manual says not to fix these yourself and to contact an authorized service provider immediately DIY 5th Gen Single-Zone Installation & Owner’s Manual, p. 37.
The manual assigns unit repairs to an authorized dealer or service provider, and any maintenance or cleaning of the outdoor unit to an authorized dealer or a licensed service provider DIY 5th Gen Single-Zone Installation & Owner’s Manual, p. 36. Electrical work goes to a qualified electrical technician DIY 5th Gen Single-Zone Installation & Owner’s Manual, p. 2. Anyone working on or breaking into the refrigerant circuit should hold a current valid certificate DIY 5th Gen Single-Zone Installation & Owner’s Manual, p. 4; in the US that is a technician certified under EPA Section 608. The service manuals warn that electricity remains in capacitors after the power is off DIY 5th Gen Single-Zone Service Manual, p. 35.
The owner’s manuals also print a “Quick Maintenance by Error Code” table that lists boards, sensors, the compressor and refrigerant to replace for each code DIY 5th Gen Single-Zone Installation & Owner’s Manual, pp. 41–42. That is parts work for a technician.
If you installed the system yourself
MrCool’s DIY manuals say two things at once. The 5th Gen DIY manual opens with “INSTALLATION MUST BE PERFORMED BY AN AUTHORIZED DEALER OR SPECIALIST” and requires a qualified electrical technician for electrical work DIY 5th Gen Single-Zone Installation & Owner’s Manual, p. 2, and then describes the installation steps. The 4th Gen E Star manual carries a disclaimer that you assume the risk of handling refrigerant under pressure, and recommends a qualified HVAC professional if you are not comfortable with the installation DIY E Star 4th Gen Installation & Owner’s Manual, p. 3. The 4th Gen multi-zone quick start says installation does not require specialized tools or training but does require basic technical skills (DIY 4th Gen Multi-Zone Quick Start, cover). The Advantage 4th Gen manual says that series “is NOT designed for amateur installation” (Advantage 4th Gen Owner’s and Installation Manual, cover).
For error codes the limits are the same whoever installed the unit: the owner’s part is the wait-and-restart procedure; wiring checks are electrical work; anything that opens the refrigerant circuit is for a certified technician. We have not reviewed MrCool’s warranty documents, so nothing here describes warranty terms.
See also
- Heat pump vs gas calculator
- R-410A after 2025: EPA rules for home AC and heat pumps
- HVAC and furnace tax credits in 2025 and 2026: 25C, 25D, 30C
Other ductless mini-splits: Daikin, Fujitsu, Mitsubishi Electric
MrCool is a trademark of its owner. How House Works is not affiliated with or endorsed by MrCool.
Sources
- MRCOOL. DIY 5th Gen Single-Zone Installation & Owner's Manual. Version Date August 5, 2026; file suffix -01; no document number printed. Cover title: DIY Series Single-Zone Mini-Split System, Installation & Owner's Manual. Accessed Oct 13, 2026.
- MRCOOL. DIY 5th Gen Single-Zone Service Manual. Version Date April 20, 2026; file suffix -01; no document number printed; same models as the owner's manual. Accessed Oct 13, 2026.
- MRCOOL. DIY 5th Gen Quick Start Guide. No Version Date and no page numbers printed; two pages, cited by PDF page. Accessed Oct 13, 2026.
- MRCOOL. DIY Select Installation & Owner's Manual. Version Date August 5, 2026; no file suffix; no document number printed. Accessed Oct 13, 2026.
- MRCOOL. DIY Select Service Manual. Version Date April 20, 2026; file suffix -01; no document number printed. Accessed Oct 13, 2026.
- MRCOOL. Easy Pro Installation & Owner's Manual. Version Date August 5, 2026; no file suffix; no document number printed. Cover title: MRCOOL DIY Easy Pro Mini-Split System. Accessed Oct 13, 2026.
- MRCOOL. Easy Pro Service Manual. Version Date April 20, 2026; no file suffix; no document number printed; covers the DE models. Accessed Oct 13, 2026.
- MRCOOL. Advantage 5th Gen Installation & Owner's Manual. Version Date September 19, 2025; file suffix -01; no document number printed. Accessed Oct 13, 2026.
- MRCOOL. Advantage 5th Gen Service Manual. Version Date March 11, 2025; file suffix -01; no document number printed. Accessed Oct 13, 2026.
- MRCOOL. DIY 5th Gen Multi-Zone Installation & Owner's Manual. Version Date January 8, 2026; file suffix -01; no document number printed. Its code table is titled “Error Display (Indoor Unit)” but lists outdoor unit codes.. Accessed Oct 13, 2026.
- MRCOOL. DIY 5th Gen Multi-Zone Service Manual. Version Date April 20, 2026; file suffix -01; no document number printed. Accessed Oct 13, 2026.
- MRCOOL. DIY 5th Gen Cassette Installation & Owner's Manual. Version Date December 02, 2025; file suffix -01; no document number printed. Cover title: DIY Series Outtasight One-Way Cassette. Accessed Oct 13, 2026.
- MRCOOL. DIY Hybrid Air Handler Installation & Owner's Manual. Version Date April 21, 2026; file suffix -01; no document number printed. Not linked from MrCool's documentation page on 2026-10-13; the file is on MrCool's own file host.. Accessed Oct 13, 2026.
- MRCOOL. DIY Hybrid Air Handler Service Manual. Version Date March 20, 2025; file suffix -01; no document number printed. Not linked from MrCool's documentation page on 2026-10-13; the file is on MrCool's own file host.. Accessed Oct 13, 2026.
- MRCOOL. Olympus Ducted Air Handler Installation & Owner's Manual. Version Date May 29, 2025; file suffix -01; no document number printed. Cover title: Olympus Series Mid-Static Ducted Air Handler. Accessed Oct 13, 2026.
- MRCOOL. Olympus Ducted Air Handler Service Manual. Version Date May 20, 2025; file suffix -01; covers the 9K to 18K units; pages are numbered within sections, cited as printed (Troubleshooting 7). Accessed Oct 13, 2026.
- MRCOOL. Mini-Split Remote Control Owner's Manual. Version Date June 1, 2026; file suffix -01; for DIY wall-mounted air handlers, Easy Pro, Advantage and Olympus wall-mounted and ceiling-recessed ducted air handlers. Accessed Oct 13, 2026.
- MRCOOL. DIY E Star 4th Gen Installation & Owner's Manual. Version Date 03-21-23; file suffix -01; no document number printed. Not listed on MrCool's documentation page on 2026-10-13; the file is on MrCool's own file host. It prints the same Version Date as the 3rd Gen E Star manual.. Accessed Oct 13, 2026.
- MRCOOL. DIY 4th Gen Multi-Zone Installation & Owner's Manual. Version Date 06-06-2023; file suffix -01; no document number printed. Not listed on MrCool's documentation page on 2026-10-13; the file is on MrCool's own file host.. Accessed Oct 13, 2026.
- MRCOOL. DIY 4th Gen Multi-Zone Troubleshooting & Solutions Guide. Version Date 10-22-21; file suffix -01; pages are numbered within the Troubleshooting section, cited as printed (Troubleshooting 4). A technician document. MrCool's documentation page labels it the owner's manual for 4th Gen DIY.. Accessed Oct 13, 2026.
- MRCOOL. DIY 4th Gen Multi-Zone Quick Start. Version Date 06-07-22; file suffix -01; Smart Controller quick start for the DIY Multi-Zone 4th Gen. Accessed Oct 13, 2026.
- MRCOOL. DIY 4th Gen Cassette Installation & Owner's Manual. Version Date 06-28-24; file suffix -01; no document number printed. Cover title: DIY Series Outtasight Ceiling Cassette Model DIYCASSETTE**HP-230C25. Accessed Oct 13, 2026.
- MRCOOL. Advantage 4th Gen Owner's and Installation Manual. Version Date 09-19-23; file suffix -01; no document number printed. Cover title: Advantage Series Owner's Manual + Installation Manual. It has no code table; the codes for this series come from the service manual.. Accessed Oct 13, 2026.
- MRCOOL. Advantage 4th Gen Service Manual. Version Date 7/06/22; file suffix -01; cover title Advantage Series Air Handler & Condenser Service Manual; pages are numbered within sections, cited as printed (Troubleshooting 5). It prints two lamp tables: one with letter codes (E1, P4, P6 and so on) and one with EH, EL, EC and PC codes. This table uses the second.. Accessed Oct 13, 2026.
- MRCOOL. DIY E Star 3rd Gen Installation & Owner's Manual. Version Date 03-21-23; file suffix -01; no document number printed. Not listed on MrCool's documentation page on 2026-10-13; the file is on MrCool's own file host. The code table's text layer is scrambled, so it was read from the page image.. Accessed Oct 13, 2026.