Note. Before performing any diagnostic test, refer to WARNINGS, 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
Malfunction code will set if average ratio between measured and maximum allowed frequency during 100 lambda regulation cycles is higher than threshold value (approximately 0.66). Check for following possible problems
- Abnormal combustion.
- Improper fuel pressure.
- Front and rear Heated Oxygen Sensor (HO2S) connections reversed.
- Intake or exhaust system leak.
- Faulty front HO2S.