Signal Circuit Inspection

Ignition "OFF" and disconnect HO2S upstream (S1) connector.
Ignition "ON".
Measure voltage between Pin No. 2 (Nernst Voltage) terminal of HO2S (S1) harness connector and chassis ground.
Measure voltage between Pin No. 1 (Virtual Ground) terminal of HO2S (S1) harness connector and chassis ground.

Measure voltage between Pin No. 3 (Pumping Current) terminal of HO2S (S1) harness connector and chassis ground.

Measure voltage between Pin No. 6 (Trim Resistor) terminal of HO2S (S1) harness connector and chassis ground.

Specification:

Nernst Voltage: Approx 2.4V

Virtual Ground Output: Approx 2.6V

Pumping Current: Approx 2.4V

Trim Resistor: Approx 2.4V
Is the measured voltage within specification?
YES
- Go to "Component Inspection " procedure.
NO
- Repair or replace as necessary and then, go to "Verification of Vehicle Repair " procedure.