Check Resistance

Turn "OFF" the ignition switch. Disconnect HO2S connector.
Measure resistance between both ends of signal terminal of HO2S (B1/S1) harness.
Specification: Approx. 0Ω
Is resistance within the specification?
YES
- Go to "GROUND CIRCUIT INSPECTION " procedure.
NO
- Repair or replace as necessary and go to "VERIFICATION OF VEHICLE REPAIR " procedure.
  NOTE: HO2S must have a clean air reference to function properly. The air is obtained by way of the sensor wire(s). Do not attempt to repair the wire(s), connector, or the terminals.