Diagnostic Trouble Code (DTC) Information

Diagnostic trouble code (DTC) information ECM-3503

Condition
A diagnostic trouble code (DTC) is stored for the relevant cylinder if the engine control module (ECM) registers that the engine is misfiring to such an extent that there is risk of damage to the three-way catalytic converter (TWC). The control module checks whether the misfire is in one cylinder or in multiple cylinders.

Substitute value
- Fuel trim disabled.

Possible source
- Low fuel level
- Many cold starts without the engine having been heated reduces the performance of the spark plugs.
- Moisture, flashover at spark plug wells
- Damaged spark plug
- Contaminated or incorrect fuel
- Blocked crankcase ventilation.
- Damaged injector or wiring
- Faulty fuel pressure
- Damaged VVT-unit.
- Uneven compression

Fault symptom[s]
- The malfunction indicator lamp (MIL) flashes
- The engine misfires
- The engine is difficult to start
- Uneven idle
- Deterioration in performance
- The engine is not firing on all cylinders.