NGC

SYMPTOM
P0455-EVAP SYSTEM LARGE LEAK

TEST NOTE
This symptom is diagnosed using the test P0442-EVAP SYSTEM MEDIUM LEAK.

WHEN MONITORED
Engine Running. Cold start test. Fuel Level greater than 12%. Ambient Temperature between 4 °C and 32 °C (39 °F and 89 °F) Close Loop fuel system. Test runs when small leak test is maturing.

SET CONDITION
The PCM activates the EVAP Purge Solenoid to pull the EVAP system into a vacuum to close the NVLD switch. Once the NVLD switch is closed, the PCM turns the EVAP Purge solenoid off to seal the EVAP system. If the NVLD switch reopens before the calibrated amount of time for a Medium leak an error is detected. Two Trip Fault.

POSSIBLE CAUSES
- Good Trip to Zero
- Leak at Gas Cap
- Vehicle History and Service Bulletin Investigation
- Visual and Physical Inspection
- Verify Evaporative Emission System Leak
- EVAP Purge Solenoid Operation
- Evaporative Emission Leak Detection
- Gas Cap
- NVLD