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
System OK. Go to "Verification of Vehicle Repair" procedure
Turn ignition switch to ON
Measure voltage for on/start input between chassis ground and ECM harnece connector.
Probe(+) : ECM harness connector NO13.
Probe(-) : Chassis ground.
Specification: Approximately 12V
Is the voltage within specification?
YES
Go to "OPEN CIRCUIT INSPECTION FOR BACK-UP POWER"
NO
Open or short circuit to chassis ground between ECM harness connector and ON/START input circuit
Repair as necessary and go to "Verification of Vehicle Repair"
With ignition switch to ON
Measure voltage of ECM Memory power circuit between ECM harness connector and chassis ground.
Probe(+) : ECM harness connector NO12.
Probe(-) : Chassis ground.
Specification: Approximately 12V
Is voltege within specification?
YES
Go to "POWER CIRCUIT INSPECTION FOR CONTROL RELAY ON INPUT"
NO
Open circuit or short circuit to chassis ground between ECM harness connector and Memory power circuit
Repair as necessary and go to "Verification of Vehicle Repair"
1.In case the voltage at terminal 12 of ECM Memory power line is 0V.
▶Possible cause : Open or short circuit in ECM memory power line which goes to ECM terminal 12 through ECM fuse(10A) in E/R-J/BOX.
With ignition switch to ON
Measure voltage of ECM Control relay ON input circuit between ECM harness connector and chassis ground.
Probe(+) : ECM harness connector NO12,14,44,63.
Probe(-) : Chassis ground.
Specification: Approximately 12V
Is the voltage within specification?
YES
Temporarily install a known good ECM and check for proper operatiuon
If problem is corrected, replace ECM
NO
Open or short circuit to chassis ground between ECM harness connector and Control relay ON input circuit
Repair as necessary and go to "Verification of Vehicle Repair"
1.In case the voltage at terminal 44,63,73 of ECM Control relay is 0V.
▶Possible cause: Open or short circuit in control relay ON input line Blown sensor fuse(10A) IN E/R-J/BOX.
