Circuit Description

WARNING: This page is about a different car, the 2002 Isuzu Trooper. However, it is still accessible from the selected car via links, so may be relevant.

Canister purge is controlled by a solenoid valve that allows manifold vacuum to purge canister. PCM supplies a ground to energize solenoid valve (purge ON). EVAP purge solenoid control is Pulse-Width Modulated (PWM) or turned on and off several times a second. Duty cycle (pulse width) is determined by engine operating conditions including load, throttle position, coolant temperature and ambient temperature. Duty cycle is calculated by PCM and output is commanded when appropriate conditions have been met.

When DTC sets, PCM illuminates MIL on second trip after fault was detected. PCM will store conditions present when DTC was set as freeze frame data in the FAILURE RECORDS data.

PCM will turn MIL off on third consecutive trip cycle during which diagnostic runs and fault is no longer recognized. A history DTC will clear after 40 consecutive trip cycles during which diagnostic runs and fault is no longer recognized. DTC can be cleared with scan tool, or by disconnecting battery voltage feed to PCM.