Diagnostic Trouble Code (DTC) Information

Diagnostic trouble code (DTC) information ECM-250A

Condition




The engine control module (ECM) receives information from the heated oxygen sensor (HO2S) about the fuel/air mixture at different loads. The diagnostic trouble code (DTC) is stored if the engine control module (ECM) registers that the fuel/air mixture deviates too much from target lambda value, leaving the long-term trim in one of its limit positions.

Substitute value
None.

Possible source

Upper limit:
- Damaged mass air flow (MAF) sensor
- Low fuel pressure
- Air leakage.

Lower limit:
- Damaged mass air flow (MAF) sensor
- High fuel pressure
- Leaking injectors
- Leaking evaporative emission system (EVAP)
- Contaminated engine oil
- Oil level too high.

Fault symptom[s]
- Malfunction indicator lamp (MIL) lit
- Poor performance
- May result in high fuel consumption.