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critical Trane
Error Code E12
Igniter relay fails, igniter open circuit. Gas valve energized when it should be off or flame current is low but allows operation.
? What Causes This
Failure of electronic control systems managing gas flow and ignition sequence.
✓ How to Fix It
Check electrical integrity of connectors between the igniter and control board. Inspect voltage levels at critical points in the circuitry.
Source: page 26 of the official manual
From the manual
This error code appears in:
Trane S9x1