Component Inspection
- Visually/physically inspect following items:
Inspect the front HO2S for any silicon contamination. This contamination will be indicated by a white powdery coating and this will result in a but false voltage signal.
If contamination is evident on the HO2S, replace contaminated sensor and go to next step.
Fig. 1) Normal value with idle after warm up : Signal is switching from rich (above 0.45V) to lean (below 0.45V) a minimum of 3 times in 10 seconds.
Fig. 2) Open in signal circuit with ignition ON : Approx. 0.4 ~ 0.5V
- Warm up the engine to normal operating temperature and check that HO2S signal is active.
- Connect Scantool and monitor the "O2 SNSR VOLT. (B1/S1)" parameter on the Scantool data list.
Specification : Verify signal is switching from rich (above 0.45V) to lean (below 0.45V) a minimum of 3 times in 10 seconds (voltage will vary between 0.1 and 0.9V).
- Is sensor switching properly?
YES
- Check for poor connection between ECM and component: backed out terminal, improper mating, broken locks or poor terminal to wire connection. Repair as necessary and go to "VERIFICATION OF VEHICLE REPAIR " procedure.
NO
- Check HO2S for contamination, deterioration, or damage. Substitute with a known-good HO2S and check for proper operation. If the problem is corrected, replace HO2S and then go to "VERIFICATION OF VEHICLE REPAIR " procedure.