Large Leak test
WARNING: This page is about a different variant/trim than selected.
Event three tests for a large leak in the EVAP system. The PCM commands the EVAP vent valve ON, CLOSED, sealing the EVAP system. This allows the vacuum pump to create a large increase in negative pressure. If the expected increase in negative pressure is not achieved, a large leak is indicated and a DTC P0455 can set. If there is no change in pressure when the vent solenoid is turned ON, the vent solenoid may be inoperative and a DTC P2420 can set.
Evaporative Emission (EVAP) Control System Description
| Diagnostic Event Sequence | Event Two | Event Three |
| EVAP Purge Solenoid | OFF/CLOSED | OFF/CLOSED |
| EVAP Vent Solenoid | OFF/OPEN | ON/CLOSED |
| Vacuum Leak Pump | ON | ON |
| FTP Sensor | Small Negative Pressure Change | Negative Pressure Increase and Hold |