Weak Vacuum Test

This tests for large leaks and blockages in the EVAP system. The PCM will command ON and close the EVAP vent valve and will command ON and open the EVAP purge valve with the engine running, allowing engine vacuum into the EVAP system. The PCM monitors the FTP sensor in order to verify that the system is able to reach a predetermined level of vacuum within a set amount of time. If the PCM does not detect the predetermined vacuum level on 2 consecutive tests, a DTC P0440 will set.