Signal Circuit Inspection

■ Check Open or Short in signal circuit 

1. IG KEY "OFF".
2. Disconnect HO2S (S1)_UP connector.
3. IG KEY "ON" & ENG "OFF"
4. Measure the voltage between Virtual Ground terminal "3" of HO2S (S1)_UP harness connector and chassis ground.

   Measure the voltage between Nernst Voltage terminal "1" of HO2S (S1)_UPharness connector and chassis ground.

   Measure the voltage between Current Pump terminal "1" of HO2S (S1)_UP harness connector and chassis ground.

   Measure the voltage between Trim Resistor terminal "4" of HO2S (S1)_UP harness connector and chassis ground.

   Specification  :

   Virtual Ground: Approx 2.5V

   Nernst Voltage: Approx 2.9V

   Current Pump: Approx 2.8V

   Trim Resistor: Approx 2.8V

5. Is the measured voltage within specification?

   YES 

   • Go to "Component Inspection " procedure.

   NO 

   • Repair Open or Short circuit and then, go to "Verification of Vehicle Repair " procedure.