Disconnect the alternator and PCM connectors and inspect for looseness, poor connection, bending, corrosion, contamination, deterioration or damage. Reconnect the connectors.

Connect the GDS and go to ""Current Data"".

Monitor PCM values in Current Data, check and wiggle the harness(es), connector(s), and terminal(s).

Any change in the values indicates a poor connection. Was a connector problem found?

	▶ Repair the connector. Go to "Verification of Vehicle Repair" procedure.
	▶ Go to "Com Circuit Inspection" procedure.

IG "OFF". Disconnect GDS.

Connect probe to COM terminal to check control waveform by using oscilloscope function.

ENG running monitor signal waveform.

Is the measured waveform within specification ?

	▶ Go to "Check Open in harness" as follows.
	▶ Go to "Check Short in harness" as follows.

IG "OFF". Disconnect Alternator and PCM connector

Measure resistant between com terminal of alternator and PCM harness connector.

Is the measured resistance within specification ?

	▶ Substitute with a known - good PCM and check for proper operation. If the problem is corrected, replace PCM and go to "Verification of Vehicle Repair" procedure.
	▶ Repair open in harness. Go to "Verification of Vehicle Repair" procedure .

IG "OFF". Disconnect Alternator and PCM connector

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

IG "ON" and measure the voltage between com terminal of the alternator harness connector and chassis ground.

Is the measured resistance and voltage within specification ?

	▶ Substitute with a known - good PCM and check for proper operation. If the problem is corrected, replace PCM and go to "Verification of Vehicle Repair" procedure.
	▶ Repair short in harness. Go to "Verification of Vehicle Repair" procedure .