When engine starting is requested, the powertrain control module (PCM) is provided a 12-volt signal through the crank request signal circuit. When this request is seen, the PCM will verify the transmission is in park or neutral and that no theft deterrent issues are present. When all conditions have been met, the PCM will ground both the powertrain relay control circuit and the starter enable relay control circuit. With the powertrain relay control circuit grounded, the powertrain relay coil will become energized and close the switch side of the relay. This will supply voltage to the coil side of the crank relay. With the starter enable relay control circuit grounded, the coil side of the crank relay will become energized and close the switch side of the relay. With the switch side of the crank relay closed, voltage is applied to the starter solenoid and engine cranking will begin.

A fault within the theft deterrent system may cause a starter solenoid does not click symptom. Verify the theft deterrent indicator is not illuminated and that the theft deterrent system is operating properly prior to using this diagnostic.

Schematic Reference

Starting and Charging Schematics

Connector End View Reference

Engine Electrical Connector End Views

Description and Operation

Starting System Description and Operation

Electrical Information Reference

Scan Tool Reference

1. Ignition ON, place the transmission in Park.
2. With a scan tool, verify the IMS or PRNDL parameter reads Park.

⇒	If the IMS or PRNDL parameter does not read Park, refer to Range Selector Displays Incorrect Range .

3. Ignition OFF, disconnect the harness connector at the ignition switch.
4. Verify a test lamp illuminates between the B+ circuit terminal F and ground.

⇒	If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.

5. Reconnect the ignition switch.
6. Disconnect the harness connector at the PCM.
7. With the ignition in the START position, verify a test lamp illuminates between the crank request signal circuit and ground.

⇒	If the test lamp does not illuminate, test the signal circuit for an open/high resistance. If all circuits test normal, test or replace the ignition switch.

8. Reconnect the PCM.
9. Disconnect the PTRAIN relay.
10. Verify a test lamp does not illuminate between the powertrain relay coil control circuit terminal and ground.

⇒	If the test lamp illuminates, test the control circuit for a short to voltage.

11. Verify a test lamp illuminates at both the coil side and the switch side B+ circuit terminals.

⇒	If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.

12. With the ignition in the START position, verify a test lamp illuminates between the B+ circuit terminal and the powertrain relay control circuit terminal.

⇒	If the test lamp does not illuminate, test the control circuit for an open/high resistance. If the circuit tests normal, replace the PCM.

13. Reconnect the PTRAIN relay.
14. Disconnect the CRANK relay.
15. Verify a test lamp does not illuminate between the starter enable relay control circuit terminal and ground.

⇒	If the test lamp illuminates, test the control circuit for a short to voltage.

16. Verify a test lamp illuminates between the switch side B+ circuit terminal and ground.

⇒	If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.

17. With the ignition in the START position, verify a test lamp illuminates between the coil side B+ circuit terminal 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, test or replace the PTRAIN relay.

18. With the ignition in the START position, verify a test lamp illuminates between the B+ circuit terminal and the starter enable relay control circuit.

⇒	If the test lamp does not illuminate, test the control circuit for an open/high resistance. If the circuit tests normal, replace the PCM.

19. Momentarily connect a 40-A fused jumper wire between the B+ terminal and the switch side control circuit terminal. Verify the starter solenoid is activated.

⇒	If the solenoid does not activate, test the control circuit for an open/high resistance. If the circuit tests normal, replace the starter motor.

20. If all circuits test normal, test or replace the CRANK relay.

1. Ignition OFF, disconnect the affected relay.
2. Test for 60-180 ohms of resistance between terminals 85 and 86.

⇒	If the resistance is not within the specified range, replace the relay.

3. Test for infinite resistance between the following terminals:

•

30 and 86

•

30 and 87

•

30 and 85

•

85 and 87

⇒	If less than infinite resistance, replace the relay.

4. Install a 20-amp fused jumper wire between relay terminal 85 and 12 volts. Install a jumper wire between relay terminal 86 and ground. Test for less than 2 ohms of resistance between terminals 30 and 87.

⇒	If greater than 2 ohms, replace the relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.