Main Relay Check
Key "OFF".
Disconnect main relay.
Measure the resistance between terminal 30 and 87 of main relay. (Component side)
Measure the resistance between terminal 85 and 86 of main relay. (Component side)
Specification :
Terminal | Power Approval |
30~87 | NO |
85~86 | YES(Approx. 70Ω ~ 120Ω) |
Is the measured resistance within specifications ?
YES
Go to "Alternator Check" procedure.
NO
Substitute with a known - good Main relay and check for proper operation.
If the problem is corrected, replace Main relay and go to "Verification of Vehicle Repair" procedure.
Alternator check
Key "OFF".
Check the tension of alternator belt.
Check corrosion, damage or looseness of Battery terminal and Alternator terminal.
Engine start.
Operate electrical parts(Head lamp, Defoger, etc).
Measure the voltage at 2000rpm.
Specification : Approx 12.5V ~ 14.5V
Is the measured voltage within specifications ?
YES
Many malfunctions in the electrical system are caused by poor harness(es) and terminals. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage. So, check poor connections and the related circuit between ECM and component thoroughly. Repair as necessary and go to "Verification of Vehicle Repair" procedure.
NO
Substitute with a known - good Alternator and check for proper operation.
If the problem is corrected, replace Alternator and go to "Verification of Vehicle Repair" procedure.