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Error code reference
Trane Furnace Error Codes
79 error codes documented with diagnostic procedures.
Have your model number? Get codes specific to your unit.
1Flame sensed when no flame should be present.1 Flash (Red)Normal LitePort data transmission1 GREENStandby mode or call for cooling.1 GREEN / 1 AMBER1st stage call for heat.1 REDFlame sensed when no flame should be present.10Gas valve energized without call for heat.10 FlashCommunication fault10 REDGas valve energized without call for heat.11Primary limit has been open for more than 5 minutes, check blower.12Ignitor relay failure internal in board12 REDIgnitor relay failure internal in board2Pressure switch is stuck closed.2 FlashFlame lost or ignition failure2 GREEN / 1 AMBER2nd stage call for heat.2 REDPressure switch stuck closed.31st stage pressure switch is stuck open (not closing).3 Double2nd stage pressure switch open3 DOUBLE RED2nd stage pressure switch open; system reverts back to 1st stage heat.3 FlashPressure switch or inducer error-a pressure switch is either opened or closed contrary to…3 GREEN / 1 AMBERW2 call present without W1.3 RED1st stage pressure switch is open or not closing.4Open primary limit, flame roll out or reverse flow switch.4 FlashHigh temperature limit fault4 GREEN / 1 AMBERY call present without G.4 REDOpen thermal limit or open rollout.5Open roll out switch or open low voltage fuse.5 FlashFlame detect fault5 REDOpen low voltage fuse.61st stage pressure switch has opened 5 times within one cycle6 FlashLine polarity fault (voltage reverse polarity), ground fault (proper earth ground not…6 RED1st stage pressure switch opened 5 times within one cycle7System lockout Retry7 FlashExternal gas valve circuit error7 REDSystem lockout Retry.8System lockout Recycle8 FlashLow flame sense signal8 REDSystem lockout Recycle.9Reverse polarity or poor grounding.9 FlashOpen inducer limit error9 REDReverse polarity or poor grounding.CFMB Blinking Red LEDFasco Motor Control Board (CFMB) has shut down due to overcurrent or overvoltage fault…ERR 10Ignition means fault-igniter fault or triac fault.ERR 101Y1 relay failure-Y1 output ON when it should be OFF or OFF when it should be ON.ERR 114Bad or missing personality module-data section corrupt, compressor size mismatch, blower…ERR 119Temperature sensor failure-temperature sensor 1 or 2 shorted or open.ERR 139Communication failure-communication message detected while configured for 24V mode.ERR 18Internal control failure.ERR 22Soft lockout due to flame lost or ignition retries (10 recycles or 3 ignition attempts…ERR 26High temp limit fault-open high limit or inducer limit; heat exchanger or flue gas…ERR 34Line polarity fault-voltage reverse polarity detected.ERR 87Flame detect fault-flame detected when it should not be present.ERR 91Communication fault-blower motor no comm response, inducer motor no comm response, loss…ERR 93Gas valve fault-control senses 24V present at gas valve when it should not be, or control…Fast FlashPersonality Module errorGreen Continuous / Red FlashingGas valve miswired or flame signal present at a call for heat.Green Fast FlashNormal operation, call for heat present.Green OFF / Red ContinuousInternal fault detected on Texas Instruments ignition control module (can occur at any…Green OFF / Red FlashingIgnition control module locked out on failure to establish flame signal.Green OFF / Red Flashing (during ignition try)No flame signal on try for ignition or flame signal lost during ignition try.Green Slow FlashNormal operation, no call for heat.Green/Red LEDs on continuouslyFuse open or internal control failure.None (AC VOLTS HI)AC line voltage too high.None (AC VOLTS LOW)AC line voltage too low.None (CAP MISMATCH)Compressor size does not match capacity in Personality Module.None (CHECK FUSE)24V control fuse is open.None (ID MTR ERR)Blower HP/OEM does not match Personality Module data.None (TS 1 OPEN)Temperature sensor 1 is open.None (TS 1 SHORT)Temperature sensor 1 is shorted.None (TS 2 OPEN)Temperature sensor 2 is open.None (TS 2 SHORT)Temperature sensor 2 is shorted.None (TWIN ERROR)Twinning not allowed with variable speedNone (Y1 OFF ERR)Y1 relay failureNone (Y1 ON ERR)Y1 output is ON when it should be OFF.RapidTwinning Error, incorrect 24V Phasing.RAPID GREEN / 1 AMBERLow flame sense current.Solid ONInternal control failure (ERR 18)Solid RedInternal gas valve circuit error (damaged furnace control)-control senses 24V at gas…Solid Red (continuous reset)Continuous reset caused by an internal error (damaged furnace control).Solid STATUS (Red OFF)24VAC fuse open-short circuit or high secondary load.
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Common questions
How do I find the error code on my Trane Furnace?
Most Trane furnaces show the code directly on the control panel display. If your model has no display, it can be read by entering diagnostic mode with the key sequence for your model. The full procedures include model-specific instructions for reading codes.
Are these codes specific to my model?
The codes here apply broadly to Trane furnaces. Meanings and diagnostic steps can vary by model and production year, so enter your model number for model-specific information and procedures.
What do I do if my code is not listed?
Some codes are model-specific or only appear in diagnostic mode. Enter your model number to get codes specific to your unit, or contact us. We update the database continuously from manufacturer service documentation.
How much does it cost to access the full diagnostic procedures?
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