Component Inspection

Visually/physically inspect following items:
- Inspect HO2S for silicon contamination from fuel or use of improper sealant. The HO2S may have a white powdery coating and this will result in a high but false voltage signal (rich exhaust indication).
Warm up the engine to normal operating temperature.
Monitor the "O2 OUT VOLT (B1S1)" parameter on scantool.
1. Specification: Verify that the 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).
  
  Fig 1: Scantool Screen Display - O2 OUT VOLT (B1S1) Parameter
Is the sensor switching properly?
YES
1. HO2S is OK.
2. Possibility of ECM fail.
3. Test with a new ECM sensor and check for proper operation. If problem is corrected, replace ECM. And go to "VERIFICATION OF VEHICLE REPAIR " procedure.
NO
1. Test with a new HO2S and check for proper operation. If problem is corrected, replace HO2S.
2. Go to "VERIFICATION OF VEHICLE REPAIR " procedure.