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 "HO2S VOLTAGE (B2S1)" 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 Display - HO2S Voltage (B2S1) Parameter
Is the sensor signal within specifications?
YES
1. Substitute with a known-good PCM and check for proper operation. If the problem is corrected, replace PCM and go to "VERIFICATION OF VEHICLE REPAIR " procedure.
NO
1. Check HO2 sensor for contamination, deterioration, or damage. Substitute with a known-good HO2 sensor and check for proper operation. If the problem is corrected, replace HO2 sensor and go to "VERIFICATION OF VEHICLE REPAIR " procedure.