Oxygen Sensor (O2)

Faults in oxygen sensor circuit may set Code 33 (and/or Code 53 on 300ZX). To test system, see CODE 33 (and/or CODE 53) diagnostic procedures in TESTS W/CODES article.

To test HEATER element of Heated Oxygen Sensor (HO2S), check resistance between outer 2 terminals of 3-wire connector. If resistance is not 3-1000 ohms, replace sensor.