Duty Cycle EVAP Canister Purge Solenoid

Fig 31 Duty Cycle EVAP Purge Solenoid:

The duty cycle EVAP purge solenoid regulates the rate of vapor flow from the EVAP canister to the throttle body The PCM operates the solenoid.

During the cold start warm-up period and the hot start time delay, the PCM does not energize the solenoid. When de-energized, no vapors are purged. The PCM de-energizes the solenoid during open loop operation.

The engine enters closed loop operation after it reaches a specified temperature and the time delay ends. During closed loop operation, the PCM energizes and de-energizes the solenoid 5 or 10 times per second depending upon operating conditions. The PCM varies the vapor flow rate by changing solenoid pulse width. Pulse width is the amount of time the solenoid energizes.

A rubber boot covers the duty cycle EVAP purge solenoid. The solenoid attaches to a bracket mounted to the right engine mount (Fig. 31). The top of the solenoid has the word TOP on it. The solenoid will not operate properly unless it is installed correctly.