Diagnostic Trouble Code (DTC) Information

Diagnostic trouble code (DTC) information

Condition
The control module receives information from the heated oxygen sensor (HO2S) about the fuel / air mixture when idling at both the lower and upper part-load range. If the fuel / air mixture deviates from lambda=1, the short-term fuel trim will compensate for this by adjusting the injection time so that lambda=1 is achieved. When the short-term fuel trim makes an adjustment, the integrator median must be adjusted by the long-term trim. Diagnostic trouble code (DTC) ECM-261A will be stored when the long-term trim must be adjusted to almost maximum in the lower part load area.

Substitute value
none

Possible source

Upper limit:
- intake air leakage
- exhaust system air leakage
- low fuel pressure
- defective heated oxygen sensor (HO2S)

Lower limit:
- intake air leakage
- high fuel pressure
- leaking injectors
- defective mass air flow (MAF) sensor
- contaminated engine oil
- oil level too high
- defective heated oxygen sensor (HO2S)

Fault symptom[s]
- none