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York furnace 4 amber flashes: thermostat G wire or reduced airflow

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HHW · ERROR-CODES · YORK · 4-AMBER-FLASHES
Based on
Johnson Controls installation manuals, wiring-diagram labels and quick reference guides

Short answer On York, Coleman and Luxaire furnaces, 4 amber flashes mean a Y signal from the thermostat without G, and the furnace still runs normally; on the modulating YP9C, CP9C, LP9C, TP9C, TM9M and TPLC family they mean reduced airflow. A technician verifies the G wire. See what to check

Furnace control LED

4 amber flashes

“No G from thermostat”

Technician

Printed on 18 model series · 11 documents

TM8X, TMLX, TM9E, TG9S, GG9S, TM9X, TM9V, DGAX, RGF19*E, TM9V*C, TM8V*C, TMLV*C, TM8T*MP, TMLT*MP, TG8S*MP, TGLS*MP, GG8S*MP, GGLS*MP · 998492-UIM-C-1013 p. 26; 6019630-UIM-F-0423 p. 36; 1083287-UIM-A-0114 p. 40; 1083288-UIM-A-0114 p. 38; 1083294-UIM-A-0114 p. 44; 5483101-UIM-A-1118 p. 29; 6019627-UIM-F-0423 p. 36; 5750149-UIM-I-0423 p. 40; 5750148-UIM-D-0423 p. 30; 995472-UIM-B-0713 p. 28; 998491-UIM-B-1013 p. 29

The lamp blinks 4 times, then pauses. It shows the count only; the timing on your board may differ.

What it means

4 amber flashes have two meanings, depending on the series. The manuals call this LED color amber.

On most York, Coleman and Luxaire furnaces, the control is receiving a Y signal from the thermostat without a G signal. The furnace operates normally in both heating and cooling, and the code is displayed to alert the user that there is a wiring problem. The installation manuals’ step is to verify that the G wire from the thermostat is connected correctly (5750149-UIM-I-0423, p. 38; 6125049-UIM-C-0624, p. 50; 6553957-UIM-A-0626, p. 91). The Y81E, RL18 and Y92V manuals call it a status code rather than a fault code (6100757-UIM-C-1124, p. 58; 6553957-UIM-A-0626, p. 91). The labels printed with the wiring diagrams read “No G from thermostat”, “Y signal with no G from thermostat” or “"Y" T-STAT CALL WITHOUT "G" CALL”; the Y92V display shows 44 (5750149-UIM-I-0423, p. 40; 5750144-UIM-H-0423, p. 37; 6553957-UIM-A-0626, p. 96).

On the modulating YP9C, CP9C, LP9C, TP9C, TM9M and TPLC, YPLC, CPLC, LPLC, 4 amber flashes mean heating capacity is reduced because of a restriction in the circulating air system, and the check is for a dirty filter or closed registers (5750151-UIM-G-0423, p. 36; 987158-UIM-B-1013, p. 30). Their label reads “Reduced Airflow problem” (5750151-UIM-G-0423, p. 39). On the same boards 5 amber flashes report reduced capacity from a restriction in the combustion air or vent system (5750151-UIM-G-0423, p. 36).

Amber is also the color of several normal states, listed in the notes below. A slow amber flash, 2 seconds on and 2 seconds off, is normal operation with a call for heat on most series (5750149-UIM-I-0423, p. 37).

Check these first

The owner’s manuals 1010352-UUM-O-0423 and 6100761-UUM-C-1124 do not list 4 amber flashes. Their amber lines are slow amber flashes, normal operation with call for heat, and double amber flashes, normal heating operation on modulating furnace models only (1010352-UUM-O-0423, p. 5). The LED is behind a clear view port in the blower compartment door (1010352-UUM-O-0423, p. 5).

On most series this code comes with normal operation in heating and cooling (5750149-UIM-I-0423, p. 38). The owner’s manual gives no step for thermostat wiring. Its troubleshooting checks are for a furnace that is not operating correctly; in the manual’s order (1010352-UUM-O-0423, p. 5):

  1. Check that electrical power to the furnace is turned on (1010352-UUM-O-0423, p. 5).
  2. Check that the manual gas shut-off valve in the gas piping supply is in the on position (1010352-UUM-O-0423, p. 5).
  3. Check that the on/off switch on the gas valve is in the on position (1010352-UUM-O-0423, p. 5). The manual reaches this switch by setting the thermostat to its lowest setting, turning off all electric power to the appliance and removing the furnace burner access panel or door (1010352-UUM-O-0423, p. 4). Use only your hand on the switch, never tools; if it does not move by hand, do not try to repair it, and call a qualified service technician (1010352-UUM-O-0423, p. 3). Turning it back on follows the full operating instructions: turning the furnace off and on.
  4. Check that the furnace blower access panel or door is correctly positioned. The electrical power supply is cut off if this door is removed (1010352-UUM-O-0423, p. 5).

On the modulating furnaces the installation manuals name two causes, a dirty filter and closed registers (5750151-UIM-G-0423, p. 36). The owner’s manual for 33-inch furnaces gives no step for registers. Filters are what the owner’s manual covers under user maintenance. They must be installed outside the furnace casing, for example in a rack on the casing or in the return air duct; if the location or the replacement process is not obvious, contact your installer or service technician (1010352-UUM-O-0423, p. 4). High-velocity filters can be cleaned with a vacuum cleaner or washed with a garden hose and must dry completely before they go back in; throwaway filters are replaced with new filters of the same size (1010352-UUM-O-0423, p. 5). Before user maintenance, 6100761-UUM-C-1124 says to make sure the area is well ventilated, turn the thermostat off, wait for a running blower to stop, turn off the gas and electrical power supplies to the furnace, and let metal parts cool to room temperature (6100761-UUM-C-1124, p. 9). The filter section is not tied to this code.

When to call a licensed technician

  • The G wire between the thermostat and the furnace. Verifying it is the installation manuals’ step (5750149-UIM-I-0423, p. 38).
  • On the modulating furnaces, the restriction in the circulating air system that the code reports (5750151-UIM-G-0423, p. 36).

Call as well if 4 amber flashes keep coming back.

Notes for different models
Series Label on the wiring diagram Installation manual text Source
TM9V*C; TM8V*C, TMLV*C (2013 and 2023); TM9V (2014); TM9E (2014 and 2023); RGF19*E; TG9S, GG9S; TM9X; TM8T*MP, TMLT*MP; TG8S*MP, TGLS*MP, GG8S*MP, GGLS*MP; TM8X, TMLX “No G from thermostat” Y signal without G; furnace operates normally in heating and cooling; verify the G wire 5750149-UIM-I-0423, pp. 38, 40; 5750148-UIM-D-0423, pp. 27, 30; 1034867-UIM-B-0913, pp. 28, 31; 1083294-UIM-A-0114, pp. 42, 44; 1083163-UIM-A-0214, pp. 36, 38; 6019630-UIM-F-0423, pp. 34, 36; 6019627-UIM-F-0423, pp. 34, 36; 1083287-UIM-A-0114, pp. 38, 40; 1083288-UIM-A-0114, pp. 36, 38; 995472-UIM-B-0713, pp. 26, 28; 998491-UIM-B-1013, pp. 27, 29; 998492-UIM-C-1013, pp. 24, 26
TM9T; TM9Y “Y signal with no G from thermostat” Same 1083286-UIM-A-0114, pp. 37, 39; 5750144-UIM-H-0423, pp. 35, 37
Y81E, RL18 “"Y" T-STAT CALL WITHOUT "G" CALL” Same; the text calls it a status code 6100757-UIM-C-1124, pp. 58, 62; 6100760-UIM-C-1124, pp. 58, 62
Y82E, Y91E, RG19, Y92E “"Y" T-STAT CALL WITHOUT "G" CALL” Same 6142403-UIM-C-1124, pp. 60, 63; 6125049-UIM-C-0624, pp. 50, 52; 6125051-UIM-C-0624, pp. 50, 52; 6154201-UIM-B-1224, pp. 78, 82
Y92V “"Y" T-STAT CALL WITHOUT "G" CALL”, display 44 Same; the text calls it a status code 6553957-UIM-A-0626, pp. 91, 96
YP9C, CP9C, LP9C, TP9C; TM9M; TPLC*C, YPLC*C, CPLC*C, LPLC*C “Reduced Airflow problem” Heating capacity reduced by a restriction in the circulating air system; check for a dirty filter or closed registers 5750151-UIM-G-0423, pp. 36, 39; 1083292-UIM-A-0114, pp. 41, 43; 1083293-UIM-A-0114, pp. 39, 41; 987158-UIM-B-1013, pp. 30, 32
DGAX “No G from thermostat” No text; label only 5483101-UIM-A-1118, p. 29
TM8X, TMLX quick reference guide Four Amber Flashes Control receiving a “Y” signal from the thermostat without a “G” signal 1060926-URG-A-1013, p. 1

Other amber patterns in the documents:

Pattern Meaning Where Source
Slow amber flash Normal operation with call for heat Installation manuals of most series; owner’s manuals 5750149-UIM-I-0423, p. 37; 1010352-UUM-O-0423, p. 5
Slow amber flash Normal operation with call for cooling Labels of the YP9C, CP9C, LP9C, TP9C and TM9M; 2013–2014 quick reference guides for the TM9V, TM8V, TM8T, TG8S and the modulating series 5750151-UIM-G-0423, p. 39; 1083293-UIM-A-0114, p. 41; 1083301-URG-A-0114, p. 1; 523354-URG-C-0513, p. 1; 521574-URG-B-0413, p. 1; 530287-URG-B-0413, p. 1; 1083298-URG-A-0114, p. 1; 535679-URG-B-0413, p. 1
2 amber flashes Normal operation with call for heat YP9C, CP9C, LP9C, TP9C, TM9M and TPLC-family manuals; 2013–2014 quick reference guides for the TM9V, TM8V, TM8T and TG8S 5750151-UIM-G-0423, p. 36; 987158-UIM-B-1013, p. 30; 1083301-URG-A-0114, p. 1; 523354-URG-C-0513, p. 1; 521574-URG-B-0413, p. 1; 530287-URG-B-0413, p. 1
Double amber flashes Normal heating operation, modulating furnace models only Owner’s manuals 1010352-UUM-O-0423, p. 5
Solid amber G call for continuous fan Y92V 6553957-UIM-A-0626, p. 86
Rapid amber flash Low flame sense current Labels of most series 5750149-UIM-I-0423, p. 40; 6125049-UIM-C-0624, p. 52
Continuous amber flash Flame sense current below 1.5 µA (TM9V*C, TM8V*C, TM9V, TM9T, TG9S, TM8T*MP, TG8S*MP) or below 0.35 µA (TM9Y, Y82E, Y91E, RG19, Y92E, Y92V) Installation manual text 5750149-UIM-I-0423, p. 37; 1083287-UIM-A-0114, p. 38; 5750144-UIM-H-0423, p. 35; 6125049-UIM-C-0624, p. 49; 6553957-UIM-A-0626, p. 87
5 amber flashes Reduced heating capacity from a restriction in the combustion air or vent system; above 4,000 ft (1,220 m) it may also be normal derating for altitude YP9C, CP9C, LP9C, TP9C, TM9M, TPLC family 5750151-UIM-G-0423, p. 36; 987158-UIM-B-1013, p. 30
Alternating red and amber flashes Refrigerant leak detected near the furnace Y81E, RL18, Y82E, Y91E, RG19, Y92E, Y92V 6100757-UIM-C-1124, p. 57; 6553957-UIM-A-0626, p. 87

The installation manuals’ checks for low flame current (cleaning the flame sensor, gas flow, a current reading) and for a refrigerant leak are technician work (5750149-UIM-I-0423, p. 37; 6553957-UIM-A-0626, p. 87).

Related York, Coleman and Luxaire codes

See also

Other gas furnaces: Carrier, Goodman, Lennox, Rheem furnaces, Trane and American Standard

All York, Coleman and Luxaire codes

York, Coleman and Luxaire are trademarks of their owners. How House Works is not affiliated with or endorsed by York, Coleman and Luxaire.

Sources

35 documents
  1. Johnson Controls. USER'S INFORMATION MANUAL MODELS: All Residential Multi-position Gas Furnaces (33 in. Models). 1010352-UUM-O-0423. File on yorknow.com, run by BHC Residential & Light Commercial LLC; YORK used under license from Johnson Controls. Accessed Oct 21, 2026.
  2. Johnson Controls. User's Information Manual: All Residential Multi-position Gas Furnaces - 33 in. Models. 6100761-UUM-C-1124. Accessed Oct 21, 2026.
  3. Johnson Controls. SINGLE STAGE ECM RESIDENTIAL GAS FURNACES MODELS: TM8X, TMLX (80% Multi-position/Standard & Low NOx) INSTALLATION MANUAL. 998492-UIM-C-1013. Accessed Oct 21, 2026.
  4. Johnson Controls. Single Stage ECM Residential Gas Furnaces Models: TM9E Series (95% AFUE Multi-position) INSTALLATION MANUAL. 6019630-UIM-F-0423. File on yorknow.com, run by BHC Residential & Light Commercial LLC; YORK used under license from Johnson Controls. Accessed Oct 21, 2026.
  5. Johnson Controls. TWO STAGE PSC RESIDENTIAL GAS FURNACES MODELS: TM9T Series (96% AFUE Multi-position) INSTALLATION MANUAL. 1083286-UIM-A-0114. Accessed Oct 21, 2026.
  6. Johnson Controls. SINGLE STAGE PSC RESIDENTIAL GAS FURNACES MODELS: TG9S and GG9S Series (95.5% AFUE Multi-position) INSTALLATION MANUAL. 1083287-UIM-A-0114. Accessed Oct 21, 2026.
  7. Johnson Controls. SINGLE STAGE ECM RESIDENTIAL GAS FURNACES MODELS: TM9X Series (95.5% AFUE Multi-position) INSTALLATION MANUAL. 1083288-UIM-A-0114. Accessed Oct 21, 2026.
  8. Johnson Controls. Modulating ECM Residential Gas Furnaces Models: YP9C, CP9C, LP9C, TP9C Series (up to 98% AFUE Multi-position) INSTALLATION MANUAL. 5750151-UIM-G-0423. File on yorknow.com, run by BHC Residential & Light Commercial LLC; YORK used under license from Johnson Controls. Accessed Oct 21, 2026.
  9. Johnson Controls. MODULATING PSC RESIDENTIAL GAS FURNACES MODELS: TM9M Series (97% AFUE Multi-position) INSTALLATION MANUAL. 1083293-UIM-A-0114. Accessed Oct 21, 2026.
  10. Johnson Controls. TWO STAGE VARIABLE SPEED ECM RESIDENTIAL GAS FURNACES MODELS: TM9V Series (96% AFUE Multi-position) INSTALLATION MANUAL. 1083294-UIM-A-0114. Accessed Oct 21, 2026.
  11. Johnson Controls. For Installation In: 1.Manufactured (Mobile) Homes 2.Recreational Vehicles & Park Models 3.Modular Homes & Buildings SEALED COMBUSTION GAS FURNACE MODELS: DGAX Single Stage - Downflow Only. 5483101-UIM-A-1118. File on yorknow.com, run by BHC Residential & Light Commercial LLC; YORK used under license from Johnson Controls. Accessed Oct 21, 2026.
  12. Johnson Controls. Single Stage ECM Residential Gas Furnaces Models: RGF19*E Series (95% AFUE Multi-position) INSTALLATION MANUAL. 6019627-UIM-F-0423. File on yorknow.com, run by BHC Residential & Light Commercial LLC; YORK used under license from Johnson Controls. Accessed Oct 21, 2026.
  13. Johnson Controls. Two Stage Standard ECM Residential Gas Furnaces Models: TM9Y Series (96% AFUE Multi-position) INSTALLATION MANUAL. 5750144-UIM-H-0423. File on yorknow.com, run by BHC Residential & Light Commercial LLC; YORK used under license from Johnson Controls. Accessed Oct 21, 2026.
  14. Johnson Controls. Two-Stage Variable Speed ECM Residential Gas Furnaces Models: TM9V*C Series (96% AFUE Multi-position) INSTALLATION MANUAL. 5750149-UIM-I-0423. File on yorknow.com, run by BHC Residential & Light Commercial LLC; YORK used under license from Johnson Controls. Accessed Oct 21, 2026.
  15. Johnson Controls. Two-Stage Variable Speed ECM Residential Gas Furnaces Models:TM8V*C, TMLV*C (80% AFUE Multi-position / Low NOx) INSTALLATION MANUAL. 5750148-UIM-D-0423. File on yorknow.com, run by BHC Residential & Light Commercial LLC; YORK used under license from Johnson Controls. Accessed Oct 21, 2026.
  16. Johnson Controls. TWO STAGE PSC RESIDENTIAL GAS FURNACE MODELS MODELS: TM8T*MP, TMLT*MP 80% AFUE Multi-position / Low NOx INSTALLATION MANUAL. 995472-UIM-B-0713. Accessed Oct 21, 2026.
  17. Johnson Controls. SINGLE STAGE PSC RESIDENTIAL GAS FURNACES MODELS: TG8S*MP, TGLS*MP, GG8S*MP, GGLS*MP (80% AFUE Multi-position / Standard Low NOx) INSTALLATION MANUAL. 998491-UIM-B-1013. Accessed Oct 21, 2026.
  18. Johnson Controls. MODULATING ECM RESIDENTIAL GAS FURNACE MODELS: TPLC*C, YPLC*C, CPLC*C, LPLC*C (80% AFUE Multi-position / Low NOx) INSTALLATION MANUAL. 987158-UIM-B-1013. Accessed Oct 21, 2026.
  19. Johnson Controls. Installation Manual: RG19 Series - Condensing Single-Stage ECM Multi- Position Gas Furnace. 6125051-UIM-C-0624. File on yorknow.com, run by BHC Residential & Light Commercial LLC; YORK used under license from Johnson Controls. Accessed Oct 21, 2026.
  20. Johnson Controls. Installation Manual: RL18 Single-Stage Standard ECM Residential Gas Furnaces (Non-condensing Multi-position Standard Low NOx). 6100760-UIM-C-1124. File on yorknow.com, run by BHC Residential & Light Commercial LLC; YORK used under license from Johnson Controls. Accessed Oct 21, 2026.
  21. Johnson Controls. Installation Manual: Y81E Single-Stage Standard ECM Residential Gas Furnaces (Non-condensing Multi-position Standard and Low NOx). 6100757-UIM-C-1124. File on yorknow.com, run by BHC Residential & Light Commercial LLC; YORK used under license from Johnson Controls. Accessed Oct 21, 2026.
  22. Johnson Controls. Installation Manual: Two-Stage Standard ECM Residential Gas Furnace Model: Y82E Non-Condensing Multi-Position/ Low-NOx Rev C. 6142403-UIM-C-1124. File on yorknow.com, run by BHC Residential & Light Commercial LLC; YORK used under license from Johnson Controls. Accessed Oct 21, 2026.
  23. Johnson Controls. Installation Manual: Y91E Series - Condensing Single-Stage ECM Multi- Position Gas Furnace. 6125049-UIM-C-0624. File on yorknow.com, run by BHC Residential & Light Commercial LLC; YORK used under license from Johnson Controls. Accessed Oct 21, 2026.
  24. Johnson Controls. Installation Manual: Y92E Series - Condensing Two-Stage Standard ECM Multi-position Gas Furnaces. 6154201-UIM-B-1224. File on yorknow.com, run by BHC Residential & Light Commercial LLC; YORK used under license from Johnson Controls. Accessed Oct 21, 2026.
  25. JC Residential and Light Commercial LLC. Installation Manual: Y92V Series - Two- Stage Variable Speed ECM Gas Furnace - Multi-Position. 6553957-UIM-A-0626. File on yorknow.com, run by BHC Residential & Light Commercial LLC; YORK used under license from Johnson Controls. Accessed Oct 21, 2026.
  26. Johnson Controls. SINGLE STAGE ECM RESIDENTIAL GAS FURNACES MODELS: TM9E Series (95% AFUE Multi-position) INSTALLATION MANUAL. 1083163-UIM-A-0214. Accessed Oct 21, 2026.
  27. Johnson Controls. TWO STAGE VARIABLE SPEED ECM RESIDENTIAL GAS FURNACES MODELS:TM8V*C, TMLV*C (80% AFUE Multi-position / Low NOx) INSTALLATION MANUAL. 1034867-UIM-B-0913. Accessed Oct 21, 2026.
  28. Johnson Controls. When paired with a York heat pump MODULATING ECM RESIDENTIAL GAS FURNACES MODELS: TP9C, YP9C, CP9C, and LP9C Series (Up to 98% AFUE Multi-position) INSTALLATION MANUAL. 1083292-UIM-A-0114. Accessed Oct 21, 2026.
  29. Johnson Controls. Quick Reference Guide - 96% AFUE Two Stage Variable Speed Multi-Position 33" Gas Furnaces. 1083301-URG-A-0114. Accessed Oct 21, 2026.
  30. Johnson Controls. Quick Reference Guide - Up To 98% AFUE 33" Modulating ECM Multi-Position Gas Furnace. 1083298-URG-A-0114. Accessed Oct 21, 2026.
  31. Johnson Controls. Quick Reference Guide - 80% AFUE Two Stage PSC Multiposition 33" Gas Furnace. 521574-URG-B-0413. Accessed Oct 21, 2026.
  32. Johnson Controls. Quick Reference Guide - 80% AFUE Two Stage ECM Multi-Position Gas Furnace 33". 523354-URG-C-0513. Accessed Oct 21, 2026.
  33. Johnson Controls. Quick Reference Guide - 80% AFUE Single Stage Multi-Position 33" Gas Furnaces. 530287-URG-B-0413. Accessed Oct 21, 2026.
  34. Johnson Controls. Quick Reference Guide - 80% Modulating Gas-Fired Residential Multi-Position Gas Furnaces with ECM Motor (33” TALL). 535679-URG-B-0413. Accessed Oct 21, 2026.
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