Signal Circuit Inspection

■ Check Short to power in signal circuit

IG "OFF".
Disconnect HO2S (S1) connector.
IG "ON".
Measure the voltage between Nernst Voltage terminal of HO2S (S1) harness connector and chassis ground.
Measure the voltage between Virtual Ground Output terminal of HO2S (S1) harness connector and chassis ground.

Measure the voltage between Current Adjust terminal of HO2S (S1) harness connector and chassis ground.

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

Specification: Approx. 0~1V
Is the measured voltage within specification?
YES
- Go to "Check Short to ground in signal circuit" procedure below.
NO
- Repair or replace as necessary and then, go to "VERIFICATION OF VEHICLE REPAIR " procedure.

■ Check Short to ground in signal circuit

IG "OFF".
Disconnect HO2S (S1) connector and ECM connector.
Measure the resistance between Nernst Voltage terminal of HO2S (S1) harness connector and chassis ground.
Measure the resistance between Virtual Ground Output terminal of HO2S (S1) harness connector and chassis ground.

Measure the resistance between Current Adjust terminal of HO2S (S1) harness connector and chassis ground.

Measure the resistance between Current Pump terminal of HO2S (S1) harness connector and chassis ground.

Specification: Infinite
Is the measured resistance within specification?
YES
- Go to "Check Short in signal circuit" procedure below.
NO
- Repair or replace as necessary and then, go to "VERIFICATION OF VEHICLE REPAIR " procedure.

■ Check Short in signal circuit

IG "OFF".
Disconnect Knock sensor connector and ECM connector.
Measure the resistance between signal 1 and signal 2 terminal of knock sensor harness connector.
Specification: Infinite
Is the measured resistance within specification?
YES
- Go to "Check Open in signal circuit" procedure below.
NO
- Repair or replace as necessary and then, go to "VERIFICATION OF VEHICLE REPAIR " procedure.

■ Check Open in signal circuit

IG "OFF".
Disconnect HO2S (S1) connector and ECM connector.
Measure the resistance between both ends of the HO2S (S1) Nernst Voltage terminal harness.
Measure the resistance between both ends of the HO2S (S1) Virtual Ground Output terminal harness.

Measure the resistance between both ends of the HO2S (S1) Current Adjust terminal harness.

Measure the resistance between both ends of the HO2S (S1) Current Pump terminal harness.

Specification: Approx. 0Ω
Is the measured resistance within specification?
YES
- Go to "COMPONENT INSPECTION " procedure.
NO
- Repair or replace as necessary and then, go to "VERIFICATION OF VEHICLE REPAIR " procedure.