EVAP Canister Purge Valve Solenoid Check

Evaporative (EVAP) Emission Canister Purge Valve Solenoid Check




Circuit Description
The evaporative emissions canister purge is controlled by a solenoid that allows manifold and/or vacuum to purge the canister when it is energized. The powertrain control module (PCM) supplies a ground to energize the solenoid valve (purge ON). The EVAP purge solenoid control is turned ON and OFF several times a second. The duty cycle (pulse width or ON time) is determined by engine operating conditions including load, throttle position, coolant temperature and ambient temperature. The duty cycle is calculated by the PCM and the purge solenoid is enabled when the appropriate conditions have been met:
- The engine run time after start is more than 60 seconds.
- The engine coolant temperature is above 30 °C (86 °F).
- The fuel control system is operating in the closed-loop mode.

Diagnostic Aids
- Make a visual check of vacuum hoses.
- Check the throttle body for possible cracked.
- Check the malfunction indicator lamp for a possible mechanical problem.

Steps 1 - 4:

Steps 5 - 12:

Steps 13 - 15:

Test Description
The number(s) below refer to the step number(s) on the Diagnostic Chart
1. Check to see if the solenoid is open or closed. The solenoid is normally de-energized in this step, so it should be closed.
2. This step checks to determine if the solenoid was open due to an electrical circuit problem or a defective solenoid.
3. This should normally energize the solenoid, opening the valve and allowing the vacuum to drop (purge ON)