Circuit/System Testing (Battery, Charging System And Starting System)

Ignition OFF, disconnect the starter relay.
Ignition OFF and scan tool disconnected, open and close the driver door and wait 1 minute. Test for less than 5.0 Ω between the relay ground circuit terminal 85 and ground.
- If greater than the specified range, test the ground circuit for an open/high resistance.
Verify a test lamp illuminates between the B+ circuit terminal 30 and ground.
- If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the control circuit terminal 87 for a short to ground.
Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 87 and ground.
- If the test lamp illuminates, test the control circuit for a short to voltage.
Parking brake applied and the transmission is in NEUTRAL or PARK. Momentarily install a 30 A fused jumper wire between the B+ circuit terminal 30 and the control circuit terminal 87. Verify the starter motor is activated.
- If the starter motor does not activate, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the starter motor.
Ignition OFF, connect a test lamp between the control circuit terminal 86 and the ground circuit terminal 85.
Transmission in park or neutral, command the starter relay ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
- If the test lamp is always ON, test the control circuit for short to voltage. If the circuit tests normal, replace the ECM.
- If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
If all circuits tests normal, replace the starter relay.