Outline Of Diagnosis

Detect abnormalities in the rear oxygen sensor output characteristics.

By referring to the intake air amount, engine coolant temperature, main feedback control, deceleration fuel cut and other operating conditions, if the rear oxygen sensor voltage should be moving under these conditions but is showing a low voltage, this is judged as a Low side NG. If the voltage is showing a high voltage, it is judged as a High side NG.

When either Low side or High side is NG, judged as rear oxygen sensor property NG.