Diagnostic Trouble Code (DTC) Information

ECM-3503 MISFIRE
DIAGNOSTIC TROUBLE CODE (DTC) INFORMATION

Condition
Diagnostic trouble code (DTC) ECM-3503 is stored for the relevant cylinder if the engine control module (ECM) registers that the engine is misfiring to such an extent that the catalytic converter may be damaged. The control module checks if the misfiring is in one specific cylinder or in multiple cylinders and also stores the relevant diagnostic trouble code (DTC) for the relevant cylinder/s.

Condition

ECM-3503:
- fuel trim disabled.

Possible source

Faulty signal:
- defective spark plugs
- defective injector, wiring
- faulty fuel pressure
- uneven compression
- moisture, flashover at spark plug wells
- low fuel level
- contaminated or faulty fuel
- many cold starts without the engine having been heated reduces the performance of the spark plugs.

Condition
- malfunction indicator lamp (MIL) flashes
- engine misfires
- engine difficult to start
- uneven idle
- poor performance
- engine not firing on all cylinders.