Diagnostic Trouble Code (DTC) Information

Diagnostic trouble code (DTC) information ECM-120C

Condition




The engine control module (ECM) calculates the expected mass air flow. The calculation is based on a number of different parameters. The calculated value for mass air flow is divided (/) by the measured value from the mass air flow (MAF) sensor (= correction value, mass air flow).
The diagnostic trouble code (DTC) is stored if the correction value deviates from 1 (higher than 1) i.e. the calculated air mass is higher than the measured air mass.
The diagnostic trouble code (DTC) can be diagnosed when the engine is running.

Substitute value
- None.

Possible source
- Air leakage in the intake system
- Contaminated throttle body (TB).
- Blocked intake system
- Damaged mass air flow (MAF) sensor.

Fault symptom[s]
- Malfunction indicator lamp (MIL) lit.
- Uneven idle