[amidgeha]

Evaporative Emission System Leak Detection Reference Orifice

5 hours after the ignition switch is turned OFF, the electric vacuum pump creates negative pressure (vacuum) in the EVAP (Evaporative Emission) system. The Engine Control Module (ECM) monitors for leaks and actuator malfunctions based on the EVAP pressure.

Cause:
Faulty Vacuum Pump Module
Vacuum Pump Module harness is open or shorted
Vacuum Pump Module circuit poor electrical connection
EVAP system hose (clogged, cracked or broken)
Faulty Engine Control Module (ECM)

Symptoms:
Check engine light