Diagnostic Trouble Code (DTC) Information

Diagnostic trouble code (DTC) information ECM-421C

Condition




The diagnostic trouble code (DTC) is stored if the engine control module (ECM) registers that the signal from the evaporative emission system (EVAP) valve is too high.
The diagnostic trouble code (DTC) can be diagnosed when the ignition is switched on.

Substitute value
- twin heated oxygen sensor (HO2S) control disabled.

Possible source
- Short-circuit to supply voltage in the signal cable
- Damaged evaporative emission system (EVAP) valve.

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