Diagnostic Trouble Code (DTC) Information

ECM-261A LONG-TERM FUEL TRIM
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 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 maximum in the lower part of the load area.

Condition
none

Possible source

Upper limit:
- intake air leakage
- exhaust system air leakage
- low fuel pressure

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

Condition
- none