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