Signal Circuit Inspection

■ Check for an open circuit 

1. IG "OFF"
2. Disconnect the alternator and ECM connector.
3. Measure the resistance from the both of alternator signal terminal in the harness connector.

   Specification:  Approx. 0 Ω

4. Is the measured resistance within specification?

   YES 

   • Go to "Check short to battery in circuit" procedure.

   NO 

   • Repair or replace as necessary and then, go to "Verification of Vehicle Repair " procedure

■ Check short to battery in circuit 

1. IG "OFF".
2. Disconnect the alternator and ECM connector.
3. IG "ON".
4. Measure the voltage between the signal terminal of Alternator harness connector and chassis ground.

   Specification:  Approx. 0 V

5. Is the measured voltage within specification?

   YES 

   • Go to "Check short to ground in circuit" procedure.

   NO 

   • Repair or replace as necessary and then, go to "Verification of Vehicle Repair " procedure

■ Check short to ground in circuit 

1. IG "OFF".
2. Disconnect the alternator and ECM connector.
3. Measure the resistance between the signal terminal of Alternator harness connector and chassis ground.

   Specification:  Infinite

4. Is the measured resistance within specification?

   YES 

   • Go to "Component Inspection " procedure.

   NO 

   • Repair or replace as necessary and then, go to "Verification of Vehicle Repair " procedure