Ho2S Inspection

Visually/physically inspect the HO2S for the following conditions:
- Ensure that the HO2S is securely installed (Pigtail and wiring harness not making contact with the exhaust pipe).
- Check for corrosion on terminals and terminal tension (at the HO2S and at the ECM)
- Front HO2S for silicon contamination. This contamination will be indicated by a white powdery coating on the portion of the sensor exposed to the exhaust stream and this will result in a but false (high) voltage signal
- Fuel, engine coolant or oil contamination
- Use of improper sealant
- If contamination is evident on the HO2S, Fix the source of the sensor contamination before replacing the sensor to prevent future contamination. Go to "VERIFICATION OF VEHICLE REPAIR " procedure.
Warm up the engine to normal operating temperature and let it idle.
Connect Scantool and monitor the "02 SNSR V0L.-B1/S1" and "02 SNSR V0L-B1/S2" parameters on the Scantool data list.
Specification: Refer to "SIGNAL WAVEFORM & DATA " procedure
- Front HO2S (O2 SNSR V0L-B1/S1): Approx. 1.5~2.0V with idle after warm up
  Sensor voltage decrease during engine acceleration and increase during engine deceleration Approx. 3.0~4.0V when fuel cut
- Rear HO2S (O2 SNSR V0L.-B1/S2): Above 0.7V at idle
Was a problem found in any of the above areas?
YES
- Repair or replace as necessary and go to "VERIFICATION OF VEHICLE REPAIR " procedure
NO
- 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