Diagnostic trouble code (DTC) information ECM-250A

Condition

Fig 1: Identifying Mass Air Flow (MAF) Sensor

Courtesy of VOLVO CARS OF NORTH AMERICA.

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.