Control Circuit Inspection

Check for open in control harness
1. Ignition "OFF".
2. Disconnect ECM connector.
3. Measure resistance between terminals 4 of the HO2S heater harness connector and 1 of the ECM harness connector.
  Specification: Approx. 0Ω
4. Is resistance within the specification?
  YES:
  - Go to step 2.
  NO:
  - Repair as necessary and go to "VERIFICATION OF VEHICLE REPAIR " procedure.
Check for short to ground in control circuit.
1. Measure resistance between terminal 4 of the HO2S heater harness connector and chassis ground.
  Specification: infinite
2. Is resistance within the specification?
  YES:
  - Go to step 3.
  NO:
  - Repair as necessary and go to "VERIFICATION OF VEHICLE REPAIR " procedure.
Check for short to power in control circuit.
1. Ignition "ON" & Engine "OFF".
2. Measure voltage between terminal 4 of the HO2S heater harness connector and chassis ground.
  Specification: Approx. 0V
3. Is voltage within the specification?
  YES:
  - Go to "COMPONENT INSPECTION " procedure.
  NO:
  - Repair as necessary and go to "VERIFICATION OF VEHICLE REPAIR " procedure.