Note. Before performing any diagnostic test, refer toWARNINGS, CAUTIONS and NOTES in DIAGNOSTIC TESTS .
Note. Testing individual components does not isolate shorts or opens. Perform all voltage tests using a Digital Volt-Ohmmeter Meter (DVOM) with a minimum 10-megohm input impedance, unless stated otherwise in test procedure. Use ohmmeter to isolate wiring harness shorts or opens.
Diagnostic Aids
Heater current of front heated oxygen sensor heater has continued to be 0.2-amps or less, or 3.5-amps or more for 6 second. Monitor runs once per trip. Check for following possible problems
- Open or short between front HO2S and Engine/Transaxle Control Module (E/TCM) or Engine Control Module (ECM).
- Short between front HO2S and E/TCM or ECM.
- Incorrect front HO2S heater resistance.
- Faulty front HO2S.