Small EVAP Leak Test

NOTE: This test may run up to three times prior to reporting a failure. A P0442 indicates a small leak anywhere between the fuel fill cap to, but not including, the purge solenoid.

The Small Leak Test runs immediately following a passing Weak Vacuum Test. While the vacuum is still present in the fuel tank, the vent valve and purge valve are both commanded closed in order to seal the system. With the system closed, the PCM monitors the trapped vacuum in the system through the fuel tank pressure sensor. If the vacuum decay rate is too fast, a small leak is indicated and a DTC P0442 is stored. Otherwise, DTC P0442 is passed and the Excess Vacuum Test - Stage 2, is run.