GM Service Manual Online
For 1990-2009 cars only

Refer to one of the following Theft Deterrent System schematics:

    • 

Theft Deterrent Control Module


Object Number: 623196  Size: FS
Master Electrical Component List
Vehicle Theft Deterrent (VTD) Description and Operation
Door Lock Actuators
License Plate Lamps, Park Lamp Relay
Horns
Serial Data Class 2
Battery Feed to the Fuse Block-Underhood
IGN SW (Fuse Block-Rear)
IGN SW Fuse (Fuse Block-Rear)
IGN SW Fuse (Fuse Block-Rear)
G201 (2 of 2)
G201 (2 of 2)
    • 

Door Lock Actuators


Object Number: 623197  Size: FS
Master Electrical Component List
Content Theft Deterrent (CTD) Description and Operation
Theft Deterrent Control Module
Serial Data Class 2

Circuit Description

The vehicle theft deterrent controller module checks the theft deterrent exciter module key data signal circuit for a constant voltage condition.

Conditions for Running the DTC

The theft deterrent controller module must see the ignition switch input. The theft deterrent controller module must have DTC B3055, Key Not Present, set as a current DTC. The theft deterrent controller module can not have a B1327 DTC set as a current DTC.

Conditions for Setting the DTC

The theft deterrent controller module requires 1 second to monitor the ignition key. After the first second, the theft deterrent controller module turns off the power to the theft deterrent exciter module. If the theft deterrent controller module senses the key data signal circuit to the theft deterrent exciter module is 12 V for 1 second, the VTD sets this DTC.

Action Taken When the DTC Sets

When the vehicle is running, the theft deterrent controller module will allow the vehicle to continue running. If the 12 V is detected on the key data signal circuit with the engine off, the theft deterrent controller module will prevent a start. The theft deterrent controller module will illuminate the security indicator.

Conditions for Clearing the MIL/DTC

The theft deterrent controller module clears the current status of the DTC when it does not sense a 12 V condition on the theft deterrent exciter module key data signal circuit. The DTC will still be retrieved as current until the ignition switch is cycled. The DTC will become a history DTC at that time.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. Make sure the ground used is separate from the grounds used by the vehicle theft deterrent controller module. Voltage measurement must not interfere with possible isolated module ground.

Step

Action

Value(s)

Yes

No

1

Did you perform A Diagnostic System Check - Theft Deterrent ?

--

Go to Step 2

Go to Diagnostic System Check - Theft Deterrent

2

  1. Turn OFF the ignition.
  2. Disconnect the theft deterrent exciter module.
  3. Turn ON the ignition leaving the engine OFF.
  4. Measure the voltage from the theft deterrent exciter module signal circuit to a good ground.

Does the voltage measure near the specified value?

0 V

Go to Step 5

Go to Step 3

3

Test the security system sensor signal circuit for a short to voltage. Refer to Circuit Testing in Wiring Systems .

Did you find and correct the condition?

--

Go to Step 8

Go to Step 4

4

Inspect for poor connections/terminal tension at the theft deterrent exciter module harness connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 8

Go to Step 6

5

Inspect for poor connections/terminal tension at the theft deterrent controller module harness connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Repairs.

Did you find and correct the condition?

--

Go to Step 8

Go to Step 7

6

Replace the theft deterrent exciter module . Refer to Theft Deterrent Excite Module Replacement .

Did you complete the replacement?

--

Go to Step 8

--

7

Important: Perform the theft deterrent controller module set up procedure.

Replace the theft deterrent controller module. Refer to Theft Deterrent Controller Module Replacement .

Did you complete the replacement?

--

Go to Step 8

--

8

  1. Clear the DTCs using the scan tool.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

--

Go to Step 2

System OK