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. 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. Diagnostic trouble code (DTC) ECM-278A will be stored if the short-term fuel trim deviates (when long-term fuel trim diagnostics are activated) too much from the center position (value) for bank 2 (cylinders 4, 5 and 6).
Diagnostic trouble code (DTC) ECM-268A is stored for bank 1 (cylinders 1, 2 and 3).

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.