For 1990-2009 cars

### Diagnostic Instructions

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

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

• | Diagnostic Procedure Instructions provides an overview of each diagnostic category.

### 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 V to the control circuit of the CRNK relay. When this occurs, battery voltage is supplied through the switch of the CRNK relay to terminal A X2 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

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Control Module References for scan tool information

### Circuit/System Verification

1. Engine running, accessories OFF, measure and record the battery voltage at the battery terminals. The voltage should be between 12.6 and 15.0 V.

⇒ | If not within the specified range, refer to Battery Charging.

2. Turn the ignition switch to the start position. The starter solenoid should click.

⇒ | If starter solenoid does not click, refer to Starter Solenoid Does Not Click.

3. Inspect the engine and belt drive system. Verify that there is no mechanical binding, seized engine, or seized generator, etc.

⇒ | If the specified conditions are observed, correct the condition.

4. Remove the drive belt, refer to Drive Belt Replacement.
5. Turn the ignition switch to the START position. The engine should crank.

⇒ | If the engine does not crank, refer to Engine Will Not Crank - Crankshaft Will Not Rotate.

6. Test for less than 0.5 V between the positive battery terminal and terminal 1 X1 at the starter solenoid as the ignition switch is turned to the START position.

⇒ | If greater than the specified value, replace the positive battery cable.

7. Test for less than 0.5 V between the negative battery terminal and the starter motor case as the ignition switch is turned to the START position.

⇒ | If greater than the specified value, replace the negative battery cable.

8. If all circuits test normal, test or replace the starter motor.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Battery Positive Cable Replacement

• | Battery Negative Cable Replacement

• | Starter Motor Replacement