GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Was the CTD System Check performed?

--

Go to Step 2

Go to Content Theft Deterrent (CTD) System Check

2

Was the BCM Diagnostic System Check performed?

--

Go to Step 3

Go to Diagnostic System Check - Body Control System in Body Control System

3

Perform the BCM Input/Output test:

  1. Turn off the I/P dimmer switch.
  2. Turn the ignition switch to the OFF position.
  3. Remove the MALL PGM fuse.
  4. Turn the ignition switch to the ACC position. The BCM sounds 4 chimes, indicating the BCM type installed on the vehicle.
  5. Within 1 second, turn the ignition switch from the ACC position to the OFF position and back to the ACC position.
  6. The BCM sounds any stored DTCs.

  7. Turn the I/P dimmer switch to the DOME position.
  8. The BCM enters the Input/Output test.

  9. Cycle the IP dimmer switch from the DOME position to the OFF position and back to the DOME position in order to move to the next test.
  10. The BCM runs the Input/Output test in numerical order.

    The BCM flashes the fasten belts indicator and sounds the chime a number equivalent to the Input/Output test number:

    • Test 1 de-energizes circuit 1393 (protected courtesy light output).
    • Test 2 energizes circuit 1393.
    • Test 3 grounds circuit 690 (courtesy lights control).
    • Test 4 turns on the headlights.
    • Test 5 sounds the horn for 25 ms.
    • Test 6 turns on the theft deterrent indicator lamp.
    • Test 7 turns off the theft deterrent indicator lamp.

Does the security indicator lamp turn on during test 6?

--

Go to Step 9

Go to Step 4

4

  1. Disconnect the security indicator lamp electrical connector.
  2. Use a test light in order to connect between the security indicator lamp connector terminal B and ground.

Does the test light illuminate?

--

Go to Step 5

Go to Step 10

5

Use a DMM on the DIODE scale in order to connect the red (+) and black (-) probes to terminals B and terminal A of the security indicator lamp.

Does the DMM show voltage B+?

--

Go to Step 6

Go to Step 11

6

  1. Disconnect the BCM connector C2.
  2. Use a test light in order to connect between the BCM harness connector C2 terminal D15 and ground.

Does the test light illuminate?

--

Go to Step 7

Go to Step 12

7

Use a DMM to measure the resistance between the BCM harness connector C2 terminal D15 and ground.

Is the resistance less than the specified value?

OL (infinite)

Go to Step 8

Go to Step 13

8

Use a DMM to connect between the BCM harness connector C2 terminal D15 and the security lamp harness connector terminal A.

Is the resistance less than the specified value?

2 ohms

Go to Step 9

Go to Step 14

9

Perform the Content Theft Deterrent System Check again. Refer to Content Theft Deterrent (CTD) System Check .

Does the theft deterrent indicator lamp operate correctly?

--

Go to Step 15

Go to Step 16

10

Repair the poor connection or the open in circuit 640.

Is the repair complete?

--

Go to Step 17

--

11

Replace the security indicator lamp.

Is the repair complete?

--

Go to Step 17

--

12

Repair the short to B+ in circuit 749.

Is the repair complete?

--

Go to Step 17

--

13

Repair the short to ground in circuit 749.

Is the repair complete?

--

Go to Step 17

--

14

Repair a poor connection or an open in circuit 749.

Is the repair complete?

--

Go to Step 17

--

15

The malfunction is not present at this time. Refer to Content Theft Deterrent (CTD) Circuit Description for more information.

Is the action complete?

--

Go to Step 17

--

16

  1. Inspect BCM connector C2 terminal D15 for poor terminal contact.
  2. Repair the terminal as needed.

  3. Inspect the security indicator lamp connector terminals A and B for poor terminal contact.
  4. Repair the terminal as needed.

  5. If all of the connector terminals are OK, replace the BCM. Refer to Body Control Module Replacement in Body Control System.

Is the repair complete?

--

Go to Step 17

--

17

  1. Turn the ignition switch to the OFF position.
  2. Reconnect all of the connectors.
  3. Reinstall any components that you removed.
  4. Turn the ignition switch to the RUN position for 6 seconds.
  5. Turn the ignition switch to the OFF position.
  6. Remove the MALL PGM fuse.
  7. Turn the ignition switch to the ACC position. The BCM flashes the fasten belts indicator and sounds the chime 4 times. This identifies the BCM type installed on the vehicle.
  8. Within 1 second, turn the ignition switch from the ACC position to the OFF position and back to the ACC position. The BCM sounds any stored DTCs.

Are there any BCM DTCs present?

--

Go to Diagnostic System Check - Body Control System in Body Control System

Go to Content Theft Deterrent (CTD) System Check