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
Engine/Transaxle Control Module (E/TCM) or Engine Control Module (ECM) monitors HO2S once per trip and will set a code when air-fuel ratio is forcibly changed (lean to rich to lean), HO2S signal does not provide response within 1.28 seconds. Check for following possible problems
- Open or short between front HO2S and E/TCM or ECM.
- Contaminated, deteriorated or aged front HO2S.
- Misplaced, bent, loose or corroded front HO2S or E/TCM or ECM connector terminals.
- Faulty front HO2S.