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.
1.2 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
System OK. Go to "Verification of Vehicle Repair" procedure
Turn ignition switch to OFF and disconnect ECM harness connector and HO2S(up,down) harness connector.
Measure voltage of HO2S heater signal circuit between HO2S harness connector and chassis ground.
Probe(+) : HO2S harness connector NO4.
Probe(-) : Chassis ground.
Specification: below 0.5V
Dose each resistance indicate continuity circuit?
YES
Go to ""Component Inspection"
NO
Short to battery between HO2S harness connector and HO2S heater signal circuit
Repair as necessary and go to "Verification of Vehicle Repair" procedure
