Diagnostic trouble code (DTC) information ECM-420D

Condition 

Fig 1: Identifying Canister Purge (CP) Valve

Courtesy of VOLVO CARS OF NORTH AMERICA.

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 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 

• Blocked hose between the EVAP canister and the evaporative emission system (EVAP) valve
• Blocked hose between the evaporative emission system (EVAP) valve and the intake manifold
• Damaged evaporative emission system (EVAP) valve.

Fault symptom[s] 

• Malfunction indicator lamp (MIL) lit.