GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2006 🢒 STS 🢒 Vehicle Control Systems 🢒 Vehicle DTC Information 🢒 Starter Noise Diagnosis

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 the following:

    •  Engine Flywheel Replacement for the 3.6L (LY7) engine
    •  Engine Flywheel Replacement for the 4.6L (LH2) engine
    •  Engine Flywheel Replacement for the 4.4L (LC3) 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