Many malfunctions in the electrical system are caused by poor harness and terminals. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.

Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.

Has a problem been found?

	▶ Repair as necessary and go to "Verification of vehicle Repair" procedure
	▶ Go to "Control Circuit Inspection" procedure.

With ignition OFF, disconnect alternator connector, and ECM connector.

Measure the resistance between FR terminal of the alternator harness connector and FR terminal of ECM harness.

Is the measured resistance within specification ?

	▶ Go to "Check short to ground" procedure.
	▶ Repair open circuit of alternator control circuit as necessary and go to "Verification of Vehicle Repair" procedure.

With ignition OFF, disconnect alternator connector, and ECM connector.

Measure the resistance between FR terminal of the alternator harness connector and chassis ground

Is the measured resistance within specification ?

	▶ Go to "Component Inspection" procedure.
	▶ Repair short circuit of alternator control circuit as necessary and go to "Verification of Vehicle Repair" procedure.

With ignition OFF, disconnect alternator connector, and ECM connector.

IG "ON"

Measure the voltage between FR terminal of the alternator harness connector and chassis ground

Is the measured voltage within specification ?

	▶ Go to "Component Inspection" procedure.
	▶ Repair short circuit of alternator control circuit as necessary and go to "Verification of Vehicle Repair" procedure.