Engine Will Not Crank

*ENGINE WILL NOT CRANK

For a complete wiring diagram Consult Diagrams/Electrical





Diagnostic Test

1. BATTERY CABLES
Turn the ignition off.

NOTE: The battery must be fully charged before diagnosing a no crank condition.

Turn the ignition off.
Inspect the battery cables for corrosion, looseness or other problems.
Is there evidence of problems?

Yes

- Repair as necessary.
- Perform the ECM Verification Test Ver. 1. Verification Tests

No

- Go To 2

2. BATTERY CABLE HIGH RESISTANCE
Check the battery cables for high resistance.
Did either battery cable have a voltage drop greater than 0.2 volts?

Yes

- Replace the battery cable(s).
- Perform the ECM Verification Test Ver. 1. Verification Tests

No

- Go To3

3. SKREEM CODES PRESENT
Turn the ignition on.
With the scan tool, read the SKREEM DTCs.
Does the scan tool display any SKREEM DTCs?

Yes

- Refer to symptom list for problems related to SKREEM.
- Perform the ECM Verification Test Ver. 1. Verification Tests

No

- Go To 4

4. CHECKING STARTER OPERATION
Turn the ignition off.
Remove the Starter Relay from the PDC.

WARNING: THE TRANSMISSION MUST BE IN NEUTRAL AND THE PARK BRAKE MUST BE SET FOR THIS TEST.

WARNING: THE ENGINE MAY CRANK IN THE NEXT STEP. WHEN THE ENGINE IS CRANKING, DO NOT STAND IN A DIRECT LINE WITH THE FAN. DO NOT PUT YOUR HANDS NEAR THE PULLEYS, BELTS OR FAN. DO NOT WEAR LOOSE CLOTHING.

Momentarily jumper Starter Relay connector cavities 30 and 87 in the PDC connector.
Did the engine crank?

Yes

- Go To 5

No

- Go To 10

5. STARTER RELAY
Install a substitute relay in place of the Starter Relay.
Attempt to start the engine.
Does the engine crank?

Yes

- Replace the Starter Relay.
- Perform the ECM Verification Test Ver. 1. Verification Tests

No

- Go To 6

6. CHECK POWER AND GROUNDS
Refer to the symptom list and perform the Checking the ECM Power and Ground test.
Were any problem found with the ECM powers and grounds?

Yes

- Repair as necessary.
- Perform the ECM Verification Test Ver. 1. Verification Tests

No

- Go To 7

7. (F942) OPEN IGNITION SW START/RUN CIRCUIT




Turn the ignition off.
Remove the Starter Relay from the PDC.
Using a 12-volt test light connected to ground, check the Ignition (F942) Switch Start/Run Output circuit while turning the ignition switch to the START position.
Does the test light illuminate with the ignition switch in the START position?

Yes

- Go To 8

No

- Repair the (F942) Ignition Switch Output circuit for an open.
- Perform the ECM Verification Test Ver. 1. Verification Tests

8. (T752) STARTER RELAY CONTROL CIRCUIT SHORTED TO VOLTAGE




Turn the ignition off.
Disconnect the ECM harness connectors.
Remove the ASD Relay from the PDC.
Using a jumper wire, connect ASD Relay connector cavities 30 and 87 in the PDC.
Turn the ignition on.
Measure the voltage of the (T752) Starter Relay Control circuit at the Starter Motor Relay connector.
Is the voltage above 1.0 volt?

Yes

- Repair the (T752) Starter Relay Control circuit for a short to voltage.
- Perform the ECM Verification Test Ver. 1. Verification Tests

No

- Go To 9

9. (T752) STARTER RELAY CONTROL CIRCUIT OPEN




Turn the ignition off.
Remove the jumper wire and install the ASD relay.
Measure the resistance of the (T752) Starter Relay Control circuit between the ECM harness connector and the Starter Relay connector in the PDC.
Is the resistance below 10.0 ohms?

Yes

- Replace the Engine Control Module.
- Perform the ECM Verification Test Ver. 1. Verification Tests

No

- Repair the (T752) Starter Relay Control circuit for an open.

10. (A901) OPEN FUSED BATTERY (+) CIRCUIT




Using a 12-volt test light connected to ground, check the (A901) Fused B+ circuit in the Starter Relay connector in the PDC.
Is the test light on?

Yes

- Go To 11

No

- Repair the (A901) Fused B(+) circuit for an open.
- Perform the ECM Verification Test Ver. 1. Verification Tests

11. (T750) STARTER RELAY OUTPUT CIRCUIT OPEN
Disconnect the (T750) Starter Relay Output wire from the Starter Solenoid.
Connect the (T750) Starter Relay Output wire (at the Starter) to ground.
Using a 12-volt test light connected to 12-volts, check the (T750) Starter Relay Output circuit at the Starter Relay connector in the PDC.
Does the test light illuminate brightly?

Yes

- Go To 12

No

- Repair the (T750) Starter Relay Output circuit for an open.
- Perform the ECM Verification Test Ver. 1. Verification Tests

12. MECHANICAL PROBLEM
Turn the ignition off.
Attempt to manually rotate the crankshaft 360°.
Is the crankshaft able to rotate 360°?

Yes

- Replace the Starter Motor.
- Perform the ECM Verification Test Ver. 1. Verification Tests

No

- Repair the engine mechanical problem.
- Perform the ECM Verification Test Ver. 1. Verification Tests