Starting and Charging: Testing and Inspection

Engine Cranks Slowly

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.

* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Reference Information

Schematic Reference

Starting and Charging Schematics [1][2]Electrical Diagrams

Connector End View Reference

Component Connector End Views Fuel Pump and Level Sensor Assembly

Description and Operation

Starting System Description and Operation Description and Operation

Electrical Information Reference

* Circuit Testing Circuit Testing

* Connector Repairs Connector Repairs

* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections

* Wiring Repairs Wiring Repairs

Scan Tool Reference

Control Module References Control Module References for scan tool information

Circuit/System Testing

1. Ignition OFF, measure and record the battery voltage at the C1 battery terminals.

2. Verify the measured voltage is between 12.0-15.0 V.

• If voltage is less than 12.0 V or greater than 15.0 V
Refer to Battery Inspection/Test Battery Inspection/Test.

• If voltage is between 12.0-15.0 V

3. Remove the drive belts. Refer to Drive Belt Replacement Service and Repair.

4. Verify the engine cranks slowly when attempting to start the vehicle.

• If the engine cranks at normal speed
Inspect the engine and belt drive system for mechanical binding, seized engine, or seized generator.

• If the engine cranks slowly

5. Verify that a test lamp illuminates between the M64 starter motor B+ terminal A X2 and ground.

• If the test lamp does not illuminate

1. Ignition OFF.

2. Test for less than 2 ohms in the B+ circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.

• If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse.

• If the test lamp illuminates

6. Test for less than 0.5 V between the positive battery cable and terminal A X2 at the M64 starter motor with the ignition in the START position.

• If 0.5 V or greater
Replace the positive battery cable.

• If less than 0.5 V

7. Test for less than 0.5 V between the negative battery cable and the M64 starter motor case with the ignition in the START position.

• If 0.5 V or greater
Replace the negative battery cable.

• If less than 0.5 V

8. Replace the M64 starter motor.

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests after completing the repair.

* Battery Positive and Negative Cable Replacement (LFX) Service and Repair

* Battery Negative Cable Replacement Battery Negative Cable Replacement

* Starter Replacement (LFX) Service and Repair