Diagnostic Trouble Code (DTC) Information ECM-421D

Condition 

Fig 1: Identifying Canister Purge (CP) Valve

Courtesy of VOLVO CARS CORPORATION

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 low.

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 ground in the signal cable.

Fault symptom[s] 

• Malfunction indicator lamp (MIL) lit.