W/Harness Inspection

P0031 HO2S Heater Control Circuit Low (Bank 1 / Sensor 1)

Inspection/Repair - W/Harness Inspection

Terminal & Connector Inspection

1. Many malfunctions in the electrical system are caused by poor harness and terminals.
Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.
2. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
3. Has a problem been found?






Power Circuit Inspection

Check Open or Short in power circuit
1. IG "OFF" & Disconnect HO2S (S1) connector.
2. IG "ON".
3. Measure the voltage between power terminal of HO2S (S1) harness connector and chassis ground.

Specification : Approx B+




4. Is the measured voltage within specification?






Control Circuit Inspection

Check Short in control circuit
1. IG "OFF" & Disconnect HO2S (S1) connector.
2. IG "ON".
3. Measure the voltage between heater control terminal of HO2S (S1) harness connector and chassis ground.

Specification : Approx. 3.5 V




4. Is the measured voltage within specification?