Diagnostic Trouble Code (DTC) Information

Diagnostic trouble code (DTC) information ECM-420C

Condition




When the control module activates evaporative emission system (EVAP) control, the idle air trim or short-term fuel trim will change. The diagnostic trouble code (DTC) is stored if the engine control module (ECM) does not detect any change in the idle air trim or in the long term fuel trim when evaporative emission (EVAP) control is active. The engine control module (ECM) interprets this as a damaged evaporative emission (EVAP) system.

Substitute value
None.

Possible source
- Damaged evaporative emission system (EVAP) valve.

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