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 continuously monitors Heated Oxygen Sensor (HO2S) activity for 90 seconds after closed loop has been enabled. During this test period, PCM counts number of times HO2S signal voltage crosses rich-to-lean and lean-to-rich threshold and how long it took to complete all transitions. PCM detects if Bank 2 HO2S indicated a rich exhaust condition while in Decel Fuel Cut Off (DFCO) for fuel control sensors.

When DTC sets, PCM will not illuminate MIL. PCM will store conditions present when DTC was set as FAILURE RECORDS data only. Information will not store as freeze frame data.

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.