Trane S8X2A040M3PSAB Error Codes

Updated October 15, 2026 · by Aurora Star Tech Inc.

Trane S8X2A040M3PSAB error codes and diagnostic codes (also listed as S8X2A040M3P). The S8X2A040M3PSAB is a Trane furnace in the Trane S8X2 series.

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Trane S8X2A040M3PSAB error codes list

Code	Meaning	Severity
---	Faults cleared confirmation	Low
CL1	Cooling, stage 1	Low
CL2	Cooling, stage 2	Low
CoF	Continuous fan demand	Low
Cr	Control code release number	Low
dFt	Outdoor defrost demand	Low
E01	Furnace control internal failure	High
E04	Open limit (main limit, rollout or reverse airflow)	High
E05	Flame sensed when no flame should be present	Critical
E08	Low flame signal (still running)	Low
E2.1	Ignition retries exceeded - flame never proven (1 hour lockout)	High
E2.2	Flame recycles exceeded - flame lost after lighting (1 hour lockout)	High
E2.3	1st stage gas valve not powered when it should be (10 times)	High
E3.1	1st stage pressure switch (PS1) closed when it should be open	Medium
E3.2	1st stage pressure switch (PS1) open when it should be closed	Medium
E3.3	2nd stage pressure switch (PS2) closed when it should be open	Medium
E3.4	2nd stage pressure switch (PS2) open when it should be closed	Medium
E6.1	120 V polarity reversed	Medium
E6.2	Ground not detected	Medium
E6.3	Igniter open or igniter relay fault	High
E7.1	1st stage gas valve (MVL) powered with no call	Critical
E11	Gas valve relay / valve circuit fault	High
E12	Control fuse open	Medium
err	Active alarm menu	Low
FD	Factory default reset done	Low
HP1	Heat pump, stage 1 demand	Low
HP2	Heat pump, stage 2 demand	Low
Ht1	Gas heat, stage 1 demand	Low
Ht2	Gas heat, stage 2 demand	Low
IdL	Idle - no demand	Low
L6F	Last 6 faults menu	Low
run	Run test mode	Low
tP1 to tP9	Blower tap in use	Low

Troubleshooting the S8X2A040M3PSAB

Blowing cold air All brands · Furnace
No heat All brands · Furnace
Short cycling All brands · Furnace
Read or clear the last 6 faults (L6F menu) Trane · Furnace
Reading and clearing fault history - Trane S-Series IFC Trane · Furnace
Reset the control to factory defaults Trane · Furnace
Run test mode (furnace) Trane · Furnace

Trane S8X2A040M3PSAB specs and setup data

Return filter size by cabinet width Trane · Furnace · Trane S8B1, Trane S8X1, Trane S8X2

All Trane Furnace error codes →

Homeowner help: Furnace Not Turning On: What to Check · Furnace Blinking Light: What the Flash Codes Mean

General guidance for qualified technicians. The manufacturer's installation and service manual and local codes always take priority. Aurora Star Tech is not affiliated with, endorsed by or sponsored by any equipment manufacturer; brand and model names are used only to identify equipment and belong to their owners.

Trane S8X2A040M3PSAB error codes list

Troubleshooting the S8X2A040M3PSAB

Trane S8X2A040M3PSAB specs and setup data

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