GM Service Manual Online
For 1990-2009 cars only

Diagnostic System Check - Theft Deterrent Immobilizer

Step

Action

Value(s)

Yes

No

1

  1. Turn the ignition switch to the ON position, with the engine OFF.
  2. Observe the Check Engine light.

Is the Check Engine light ON steady?

--

Go to Step 2

Go to Engine Controls

2

  1. Install the scan tool.
  2. Establish communication with the ECM.

Does the scan tool communicate with the ECM?

--

Go to Step 4

Go to Step 3

3

Refer to Scan Tool Does Not Communicate with ECM in Data Link Communications.

Is the repair procedure complete?

--

System OK

--

4

Attempt to start the engine.

Does the engine start?

--

Go to Step 5

Go to Step 12

5

  1. Select IMMOBILIZER on the scan tool.
  2. Turn ON the ignition switch.
  3. Establish communication with the theft deterrent module.

Does the scan tool communicate with the theft deterrent module?

--

Go to Step 7

Go to Step 6

6

Refer to Scan Tool Does Not Communicate with TDM (Immobilizer) in Data Link Communications.

Is the repair procedure complete?

--

System OK

--

7

Select DTC Information.

Do any current DTCs display?

--

Go to Step 8

Go to Step 9

8

Refer to Diagnostic Trouble Code (DTC) List/Type for diagnosis of the DTC that is present.

Is the repair procedure complete?

--

System OK

--

9

Do any history or intermittent DTCs display?

--

Go to Step 10

Go to Step 11

10

An intermittent problem is present. Refer to the diagnostic aids for the appropriate DTC for diagnosis of the intermittent problem.

Is the repair procedure complete?

--

System OK

--

11

Attempt to start the engine again.

Does the engine start properly?

--

System OK

Go to Step 12

12

Test the following engine systems for basic malfunctions. Refer to Engine Controls for specific test procedures.

    • Fuel system
    • Ignition system
    • General engine condition

Was a problem found and repaired with any of the engine systems?

--

System OK

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