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).
- Replace HO2S as necessary and go to next step.
  
  Fig 1: Inspecting HO2S For Silicon Contamination
Warm up the engine to normal operating temperature.
Monitor the "O2 OUT VOLT (B2S2)" parameter on scantool.
1. Specification: Approx. 0.6~0.7V
  
  Fig 2: Scantool Screen Display - O2 OUT VOLT (B2S2) 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.