GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The security indicator is used by both the vehicle theft deterrent (VTD) system and the content theft deterrent (CTD) system. The security indicator is controlled by the body control module (BCM) via the security indicator control circuit. When VTD or CTD requests the security indicator be illuminated, the BCM grounds the security indicator control circuit, illuminating the security indicator.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC B0688 Security System Indicator Circuit High

Conditions for Setting the DTC

The BCM detects a short to battery in the security indicator control circuit.

Action Taken When the DTC Sets

The BCM will set and store DTC B0688.

Conditions for Clearing the MIL/DTC

    • The BCM no longer detects a short to battery in the security indicator control circuit.
    • A scan tool is used to clear the DTC.

Step

Action

Yes

No

Schematic Reference: Theft Deterrent System Schematics

Connector End View Reference: Theft Deterrent System Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

  1. Turn ON the ignition, with the engine OFF.
  2. With the scan tool, command the security indicator ON and OFF.

Does the security indicator turn ON and OFF with each command?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3

Test for a short to battery in the security indicator control circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 6

Go to Step 4

4

Inspect for poor connections at the harness connector of the body control module (BCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 6

Go to Step 5

5

Replace the BCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 6

--

6

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 1