Diagnostic Aids

WARNING: This page is about a different car, the 2002 Pontiac Sunfire, 2002 Pontiac Grand Am, 2002 Oldsmobile Alero, and 2002 Chevrolet Cavalier. However, it is still accessible from the selected car via links, so may be relevant.

An intermittent could be the result of a faulty electrical connection, moisture in the electrical connector or connector wiring, rubbed-through wire insulation or broken wire inside the insulation.
Inspect for a faulty electrical connection or a damaged harness. Inspect PCM harness for an open in HO2S 2 signal circuit. Inspect for improper mating, broken locks, improperly formed connectors, damaged terminals, faulty terminal-to-wire connection or damaged harness.
An intermittent test - observe the HO2S 2 on the scan tool while moving the related electrical connectors and the wiring harness with the ignition switch turned ON. If the malfunction is induced, the HO2S 2 display will change. This should help to isolate the location of the malfunction.
Obstruction of the air reference and degraded HO2S 2 performance could result from any attempt to repair the above conditions. The HO2S 2 must have a clean air reference in order for the HO2S 2 to function properly. This clean air reference is obtained by way of the HO2S 2 wires.