York furnace error codes
This page covers York TM9E single-stage ECM gas furnaces as documented in installation manual 6019630-UIM-F-0423. The control uses one LED that can show red, amber or green, and the color matters: four red flashes and four amber flashes mean different things. Confirm the full model number and the label on the installed furnace before relying on this chart, because other York and Johnson Controls furnaces and replacement boards can use different tables. A code describes what the control detected, not which part failed.
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How to read the tri-color LED
Fault codes are groups of flashes about a third of a second on and a third off, with a 2-second gap between groups. Note the color as well as the count. A slow flash of 2 seconds on and 2 seconds off is normal: green means no thermostat call, amber means a heat call is present. Slow amber does not prove the burner is lit, and it is not a one-flash fault. No LED, or an LED lit steadily in any color, points to a power or control problem. Read the LED through the existing viewing port.
What this chart covers
The chart has 16 live rows: eleven red fault codes (1 to 11), one amber warning of four flashes, two normal slow-flash states, and the no-LED and steady-on control states. Two green acknowledgements (2 and 3 flashes) appear only in the technician's LAST ERROR memory mode and are left out. Two amber flashes, a normal heating state for modulating furnaces only, does not apply to the single-stage TM9E. Models covered are the ten MP12 models from TM9E026A08MP12 to TM9E120D20MP12 listed in the TM9E technical guide.
- York TM9E single-stage ECM tri-color LED control: TM9E
TM9E LED code chart (manual 6019630-UIM-F-0423)
| Code or flash pattern | Meaning | Model family | Details |
|---|---|---|---|
| Red LED: 1 flash, then 2-second pause | Flame Without Heat Call The control sensed flame when there was no call for heat. In response it runs the combustion-air inducer and the supply-air blower. | TM9E | View details |
| Red LED: 2 flashes, then 2-second pause | Pressure Switch Closed At the start of a heat cycle the pressure switch was already closed when the control expected it open. The control blocks the ignition sequence while this condition exists. | TM9E | View details |
| Red LED: 3 flashes, then 2-second pause | Pressure Switch Open The control expected the pressure switch to be closed and found it open. York lists several checks for this, so the code alone does not prove a failed switch. | TM9E | View details |
| Red LED: 4 flashes, then 2-second pause | Main Limit Open The main limit switch is open, and the supply blower and inducer keep running while it stays open. Five openings in one heat demand cause a 1-hour soft lockout; if it stays open past 5 minutes, the code changes to 11 red. | TM9E | View details |
| Red LED: 5 flashes, then 2-second pause | Rollout Switch Open The manual-reset rollout safety switch has opened. The control goes into a hard lockout that York permits clearing only after the problem is corrected. | TM9E | View details |
| Red LED: 6 flashes, then 2-second pause | Pressure Switch Lockout The pressure switch opened four times during one heat call. The control then locks out for one hour before an automatic retry. | TM9E | View details |
| Red LED: 7 flashes, then 2-second pause | Ignition Failure The furnace made three ignition trials without establishing flame. The control then locks out for one hour and retries automatically. | TM9E | View details |
| Red LED: 8 flashes, then 2-second pause | Repeated Flame Loss Flame was lost five times during heating, which corresponds to four recycles. The control locks out for one hour, then retries automatically. | TM9E | View details |
| Red LED: 9 flashes, then 2-second pause | Polarity or Ground Fault The control has detected reversed line-voltage polarity, a grounding problem, or reversed low-voltage transformer wires. Heating and cooling are both affected, and ignition is blocked until it is corrected. | TM9E | View details |
| Red LED: 10 flashes, then 2-second pause | Gas Valve On Without Call The control detects the gas valve energized when there is no call for heat. The inducer and main blower run, and no ignition sequence starts while it persists. | TM9E | View details |
| Red LED: 11 flashes, then 2-second pause | Limit Open Too Long The main limit has stayed open for more than 5 minutes, putting the control in a hard lockout. York says the lockout should be cleared only after the problem is corrected. | TM9E | View details |
| Amber LED: 4 flashes, then 2-second pause (not 4 red) | Thermostat Wiring Warning The control received a thermostat Y signal without a G signal. York states heating and cooling still operate normally; the indication flags a wiring issue and is unrelated to the four-red limit fault. | TM9E | View details |
| Green LED slow flash: 2 seconds on, 2 seconds off | Normal Standby The furnace control is operating normally with no thermostat calls. This is the standby state, not a fault code. | TM9E | View details |
| Amber LED slow flash: 2 seconds on, 2 seconds off | Normal Heat Call The control is operating normally with a heat call present. This slow amber flash is a status, not a one-flash fault, and does not by itself confirm the burner is lit. | TM9E | View details |
| LED off (no color showing) | No LED Indication No LED is displayed. York lists lost control power, a blown fuse or a control failure as possible reasons, so a dark LED alone does not identify a failed board. | TM9E | View details |
| LED steady on in red, green or amber, no flashing | Control Failure An LED lit steadily in red, green or amber indicates a control failure. York states the control is not field repairable. | TM9E | View details |
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