RAM 3500 Truck 2WD V10-8.0L VIN W (1997)
Canister Purge Solenoid: Description and Operation
Duty Cycle EVAP/Purge Solenoid
Fig. 3 EVAP Purge Solenoid
DESCRIPTION
All engines use a duty cycle EVAP canister purge solenoid. The solenoid regulates the rate of vapor flow from the EVAP canister to the throttle
body. The Powertrain Control Module (PCM) operates the solenoid.
OPERATION
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 deenergizes 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. The PCM adjusts solenoid pulse width based on engine
operating condition.
