W/Harness Inspection

Engine Control
P0620 Alternator Control Circuit - Inspection/Repair:_:W/Harness Inspection

Terminal and Connector inspection

1. 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.
2. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
3. Has a problem been found?






Control Circuit Inspection

Check waveform
1. IG "OFF" and connect GDS.
2. Connect probe to COM terminal to check control waveform by using oscilloscope function.
3. ENG "ON" and monitor signal waveform.

Specification :Compare actual waveform to those in figures 1- 4.








4. Is the measured waveform within specification ?





Check Open in harness
1. IG "OFF" and disconnect Alternator and PCM connector
2. Measure resistant between com terminal of alternator and PCM harness connector.

Specification :Below 1Ohms








3. Is the measured resistance within specification ?





Check Short in harness
1. IG "OFF" and disconnect Alternator and PCM connector
2. Measure the resistance between com terminal of the alternator harness connector and chassis ground.
3. IG "ON" and measure the voltage between com terminal of the alternator harness connector and chassis ground.

Specification :(2.) Approx. below 1Ohms, (3.) Approx. 0V








4. Is the measured resistance and voltage within specification ?