SureTrack Real Fix: Purge Those Problems

Once again problems with the EVAP problem can be tricky to diagnose. Follow this Real Fix to see how using a smoke machine aided in tracking down the issue on this Volvo V70.

Vehicle
2001 Volvo V70 T-5 2.3L

Title
P0442, P0455, Replaced EVAP Purge Solenoid Valve

Complaint
The customer states the check engine light is on.

Cause
Connected a scan tool and found codes: P0442 – Evaporative Emission System Leak Detected (Small Leak); P0455 – Evaporative Emission System Leak Detected (Large Leak) and P1171 – Long Term Fuel Trim Upper Limit. With the scan tool connected, performed an on board evaporative emission (EVAP) system leakage test and found the system did not go into negative pressure. Connected a smoke machine to the evaporative emission (EVAP) system, performed a smoke test with the smoke machine, and found no apparent external smoke leakage. Removed the vacuum supply hose from the EVAP purge solenoid valve fitting and found smoke leaking from the fitting. Disconnected the connector from the EVAP purge solenoid valve and smoke continued to leak from the fitting. Used a multi-meter and measured the specified 12 Volts and less than 100mv ground at the connector with solenoid energized with the scan tool and found voltage and ground were present. Removed the EVAP purge solenoid valve, used a set of fused jumper wires, applied 12 Volts and ground to the solenoid while applying vacuum with a hand held vacuum pump. With the valve energized or not energized the valve did not hold a vacuum indicating the EVAP purge solenoid valve was faulty.

Correction
Replaced the EVAP purge solenoid valve, cleared codes, performed a road test and verified the vehicle operated properly. The check engine light did not illuminate and no fault codes returned.