Diagnostic Instructions
Circuit/System Description
When the ignition switch is placed in the START position, a discrete signal is supplied to the body control module (BCM) notifying it that the ignition is in the START position. The BCM then sends a message to the engine control module (ECM) that crank
has been requested. The ECM then verifies that the transmission is in Park or Neutral. If it is, the ECM then supplies 12 volts to the control circuit of the STARTER relay. When this occurs, battery voltage is supplied through the switch of the STARTER
relay to S terminal of the starter solenoid.
Reference Information
Schematic Reference
Starting and Charging Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Starting System Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References
Circuit/System Verification
- Verify that battery is sufficiently charged and that the battery cables are clean and tight.
- Turn the ignition switch to the start position. The starter solenoid should click.
- Remove the drive belt. Refer to
Drive Belt Replacement for the 3.5 L engine
Drive Belt Replacement for the 3.9 L engine
Drive Belt Replacement - Accessory for the 5.3 L engine.
- Turn the ignition switch to the START position.
⇒ | If the engine cranks, inspect the engine and belt drive system for mechanical binding, seized engine, or seized generator, etc. |
- Test for less than 0.5 volts between the positive battery cable and terminal 1 X1 at the solenoid as the ignition switch is placed to the START position.
⇒ | If greater than the specified value, replace the positive battery cable. |
- Test for less than 0.5 volts between the negative battery cable and the starter motor case as the ignition switch is placed to the START position.
⇒ | If greater than the specified value, replace the negative battery cable. |
⇒ | If all circuits test normal, replace the starter motor. |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic procedure.