Control Circuit Inspection

■ Check voltage 

1. IG "OFF". Disconnect HO2S (B1/S1) connector.
2. IG "ON".
3. Measure voltage between control terminal of HO2S (B1/S1) heater harness connector and chassis ground.

   Specification:  Approx. 3.5 V

4. Is the measured voltage within specification?

   YES 

   • Go to "COMPONENT INSPECTION " procedure.

   NO 

   • Repair short to battery in HO2S (B1/S1) Heater control circuit. Go to "VERIFICATION OF VEHICLE REPAIR " procedure.