3.
Measure resistance between terminals 2 of the sensor harness connector(C39) and ECM(20/C23-2)
1)
Specification : Approx. 0Ω
Ignition "OFF" & Engine "OFF"
Disconnect HO2S connector
Measure resistance between terminals 2 of the sensor harness connector(C39) and ECM(20/C23-2)
Specification : Approx. 0Ω
Is resistance within specifications?
YES
Go to "Signal Circuit Inspection" procedure
NO
Repair open in the ground circuit and go to "Verification of Vehicle Repair" procedure
Measure resistance between terminals 1 of the sensor harness connector(C39) and ECM(14/C23-2)
Specification : Approx. 0Ω
Is resistance within specifications?
YES
Go to "Heater Circuit Inspection" procedure
NO
Repair open or short in the signal circuit and go to "Verification of Vehicle Repair" procedure
Ignition "ON" & Engine "OFF"
Measure voltage between terminal 3 of the HO2S heater harness connector(C39) and chassis ground.
Specification : Approx. B+
Is voltage within specifications?
YES
Go to next step.
NO
Check for an open in the power supply circuit between the main relay and the HO2S.
Repair as necessary and go to "Verification of Vehicle Repair" procedure
Check for open in control harness
Ignition "OFF" & Engine "OFF"
Measure resistance between terminals 4 of the HO2S heater harness connector(C39) and ECM(1/C23-2)
Specification : Approx. 0Ω
Check for short to ground in control circuit
Measure resistance between terminal 4 of the HO2S heater harness connector(C39) and chassis ground
Specification : infinite
Are measurements OK?
YES
Go to "Terminal and Connector Inspection" procedure
NO
Repair open or short to ground in control circuit and go to "Verification of Vehicle Repair" procedure
Many malfunctions in the electrical system are caused by poor harness(s) and terminals. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.
Check the following conditions:
Check for damaged harness and terminals: contact resistance, oxidation, bent or broken terminals.
Check for poor connection between ECM and component: backed out terminal, improper mating, broken locks or poor terminal to wire connection
Use a suitable male pin to ensure that contact in sockets is good. The pin should remain in position when pulled gently.
Has a problem been found?
YES
Repair as necessary and go to "Verification of Vehicle Repair" procedure
NO
Test with a new HO2S and check for proper operation. If problem is corrected, replace HO2S sensor and go to "Verification of Vehicle Repair" procedure
