Cavalier/Z24 L4-138 2.3L DOHC VIN D MFI (1995)
EVAP Purge Vaccum Switch: Testing and Inspection
SCAN TOOL TESTING
The EVAP Purge Vacuum Switch can be diagnosed with the use of a scan tool. When purge is commanded by the PCM and the throttle is opened
off idle, the scan tool should display the EVAP Vac Switch as "OFF" indicating that the normally closed switch is open or that purge is occurring.
When vacuum is not present or canister purging is not taking place, the switch will be closed or "ON."
The EVAP canister purge valve operation is covered in Chart C-3 EVAP Canister Purge Valve Check and also in DTCs P0441 and P1441. The
EVAP purge vacuum switch is diagnosed by DTCs P0441 and DTC P1441.
A open or shorted circuit in the purge valve can also be diagnosed in Chart C-20 PCM Outputs. See: Computers and Control Systems/Testing
and Inspection
