Symptom Related Diagnostic Procedures

Generator Noise Diagnosis

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 Electrical Diagrams

Connector End View Reference

Component Connector End Views Sunshade - Left (DH6)

Description and Operation

Charging 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

Diagnostic Aids

Noise from a generator may be due to electrical or mechanical noise. Electrical noise or magnetic whine usually varies with the electrical load placed on the generator and is a normal operating characteristic of all generators. When diagnosing a noisy generator, it is important to remember that loose or misaligned components around the generator may transmit the noise into the passenger compartment and that replacing the generator may not solve the problem.

Circuit/System Verification

1. Ignition OFF, measure the voltage across the battery terminals. The voltage should read 12.0 V or greater.

• If not within the specified range, refer to Battery Inspection/Test Battery Inspection/Test.

2. Verify that there are no A/C lines, heater hoses or other accessory equipment misrouted or rubbing against the generator causing the noise to be transmitted into the passenger compartment.

• If there is a line rubbing condition, reroute or realign the hose or line.

3. Remove the engine drive belt. Verify all the belt driven devices listed below spin freely and do not produce any unusual sounds.

• If they do not spin freely or they make an unusual sound replace the affected component.

4. Inspect the generator, its alignment, and its bolt torque, refer to Generator Replacement (LE9) Generator Replacement (LE9)Generator Replacement (LF1) Generator Replacement (LF1)

• If misaligned or improperly torque, correct the alignment and/or torque issue.

5. Engine running, verify that the noise concern is not engine related.

• If it is engine related noise, refer to the engine mechanical diagnostic information and procedures for the appropriate engine.

6. Ignition OFF, install the engine drive belt.

7. Engine running, verify the generator is not producing unusual noise.

• If the generator is making more than usual noise, replace the generator.

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.