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.

PCM checks validity of signals used in ION Sensing Module at various engine operating conditions. Test will return a fault if cylinder synchronization routine has not been completed after a predetermined number of events after crank. Test will detect fault that will prevent PCM from synchronization, such as Knock Signal (KI), Combustion Quality (CQ) lines being swapped, shorted spark plugs, ION Sensing Module faults and PCM hardware faults.

When DTC sets, PCM illuminates MIL as soon as fault was detected. PCM calculates an air flow value based on idle air control valve position, throttle position, RPM and barometric pressure. 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.