Diagnostic Trouble Code (DTC) Information ECM-120D
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 (lower than 1) i. e. the calculated air mass is lower 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