GM Service Manual Online
For 1990-2009 cars only

Diagnostic Aids

Inspect the flywheel ring gear for damage or unusual wear.

Test Description

The number below refers to the step number on the diagnostic table.

  1. A starter motor that remains engaged after engine start up can be cause by a starter relay that hangs up or a low current short to B+ on the starter solenoid crank voltage circuit. Verify the integrity of the starter solenoid crank voltage circuit before replacing the starter motor.

Step

Action

Yes

No

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

Start the engine.

Does the starter operate normally?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

Start the engine while listening to the starter motor turn.

Is there a loud "whoop", that may sound like a siren if the engine is revved while the starter is engaged, after the engine starts, but while the starter is still held in the engaged position?

Go to Step 6

Go to Step 4

4

Do you hear a "rumble", a "growl", or, in some cases, a "knock" as the starter is coasting down to a stop after starting the engine?

Go to Step 7

Go to Step 5

5

Important: This is often diagnosed as a starter drive gear hang-in or a weak solenoid.

When the engine is cranked, do you hear a high-pitched whine after the engine cranks and starts normally?

Go to Step 8

Go to Step 7

6

Inspect the flywheel ring gear for the following:

    • Chipped gear teeth
    • Missing gear teeth
    • Milled teeth

Is the flywheel bent, or does it have damaged teeth?

Go to Step 8

Go to Step 7

7

  1. Remove the starter motor. Refer to Starter Motor Replacement .
  2. Inspect the starter motor bushings and clutch gear.

Does the clutch gear have chipped or milled teeth or worn bushings?

Go to Step 9

Go to Step 10

8

Replace the flywheel. Refer to Engine Flywheel Replacement for the 2.8L (LP1) engine, Engine Flywheel Replacement for the 3.6L (LY7) engine, or Engine Flywheel Replacement for the 6.0L engine.

Did you complete the replacement?

Go to Step 10

--

9

Replace the starter motor. Refer to Starter Motor Replacement .

Did you complete the replacement?

Go to Step 10

--

10

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3