GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 1999 🢒 Grand Prix 🢒 DTC 🢒 DTC 1 Fasten Seat Belt Indicator Control Circuit Shorted B+ or Ground

Circuit Description

The body control module (BCM) controls the operation of the fasten seat belt indicator. The fasten seat belt indicator is located in the instrument cluster. The BCM turns ON the fasten seat belt indicator by analyzing the voltage through CKT 529. The fasten seat belt indicator receives ground through CKT 1450. The BCM turns ON the fasten seat belt indicator for 6 seconds when the following conditions are met:

    • The ignition switch is tuned from the OFF position to the RUN position.
    • When the BCM turns ON the fasten seat belt indicator, the BCM will sound the chime at a rate of 50 chimes per second. If the drivers seat belt is fastened during the 6-second period the BCM turns OFF both the fasten seat belt indicator and the chime.

Conditions for Setting the DTC

The BCM detects a short to B+ or ground in CKT 529.

Action Taken When the DTC Sets

The following actions are taken when the DTC sets:

    • The BCM sets the diagnostic trouble code (DTC) 1.
    • The fasten seat belt indicator lamp does not turn ON when CKT 529 is shorted to ground.
    • The fasten seat belt indicator lamp stays on at all times when CKT 529 is shorted to B+.

Conditions for Clearing the DTC

The following are the conditions for clearing the DTCs:

    • A short to B+ or ground in CKT 529 is no longer present between the BCM and the instrument cluster.
    • After the repairs are completed, refer to Body Control Module Diagnostic Information in order to clear the DTC.

Diagnostic Aids
    • Inspect for a short to ground in CKT 529.
    • Inspect for a short to B+ in CKT 529.
    • An internal short to ground in the instrument cluster circuitry.
    • Perform the following test while moving the wiring and connectors. This will cause the malfunction to appear.

Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

  1. Always perform the BCM diagnostic system check before attempting to diagnose this DTC.

    2.

  2. This step checks for operation of the fasten seat belt indicator.

    3.

  3. This step checks for a short to ground on CKT 529.

    4.

  4. This step checks for a short to B+ in CKT 529.

    5.

  5. This step determines whether the BCM or the instrument cluster is faulty.

    6.

  6. This step checks for a faulty BCM.

Fasten Belt Indicator Lamp Control Circuit Shorted to B+ or Ground

Step

Action

Value(s)

Yes

No

1

Was the BCM Diagnostic System Check performed?

--

Go to Step 2

Go to Diagnostic System Check - Body Control System

2
  1. Turn the ignition switch to the OFF position.
  2. Release (unfasten) the driver's seat belt.
  3. While observing the fasten seat belt indicator, turn the ignition switch to the RUN position.

Does the fasten seat belt indicator turn ON for 6-8 seconds, then turns off?

--

Go to Step 7

Go to Step 3

3
  1. Turn the ignition switch to the OFF position.
  2. Disconnect the Body Control Module (BCM) electrical connector C2.
  3. Disconnect the instrument cluster electrical connector C2.
  4. Use a DMM in order to measure the resistance between the BCM harness connector C2 terminal D12 and ground.

Is the resistance equal to the specified value?

OL (infinite)

Go to Step 4

Go to Step 8

4
  1. Turn the ignition switch to the RUN position.
  2. Use a DMM in order to measure the voltage between the BCM harness connector C2 terminal D12 and ground.

Is the voltage less than the specified value?

2 V

Go to Step 5

Go to Step 9

5
  1. Reconnect the instrument cluster electrical connector C2.
  2. Use a 3A fused jumper to connect between the B+ and the BCM harness connector C2 terminal D12.

Does the fasten seat belt indicator lamp turn ON (and fused jumper does not open)?

--

Go to Step 6

Go to Step 10

6
  1. Turn the ignition switch to the OFF position.
  2. Disconnect fused jumper (from step 5).
  3. Reconnect the BCM electrical connector 2.
  4. Make sure driver's seat belt is released (unfastened).
  5. Turn the ignition switch to the RUN position for 6 seconds
  6. Turn the ignition to the OFF position.
  7. Remove the MALL PGM Fuse.
  8. Turn the ignition switch to the ACC position. (The BCM sounds the chime a number of times equivalent to the BCM type installed on the vehicle).
  9. Within one second, turn the ignition switch from the ACC position, to the OFF position, then back to the ACC position. (The BCM sounds any DTCs stored).

Does DTC 1 reset?

--

Go to Step 7

Go to Step 11

7

Malfunction is intermittent or not present at this time. Refer to Diagnostic Aids for more information.

Is the repair complete?

--

Go to Step 12

--

8

Repair short to ground in CKT 529.

Is the repair complete?

--

Go to Step 12

--

9

Repair the short to B+ in CKT 529.

Is the repair complete?

--

Go to Step 12

--

10
  1. Inspect the BCM connector C2 terminal D11 for a short to B+ or ground and perform necessary connector repairs.
  2. If connector is OK, then replace the BCM. Refer to Body Control Module Replacement .

Is the repair complete?

--

Go to Step 12

--

11

Malfunction is not present at this time. Refer to Diagnostic Aids for additional information.

Is the action complete?

--

Go to Step 12

--

12
  1. Turn the ignition switch to the OFF position.
  2. Reinstall connectors/components removed.
  3. Remove the MALL PGM Fuse.
  4. Turn the ignition switch to the ACC position. (The BCM sounds the chime a number of times equivalent to the BCM type installed on the vehicle).
  5. Within one second, turn the ignition switch from the ACC position, to the OFF position, then back to the ACC position. (The BCM sounds any DTCs stored).

Are there any BCM DTCs present?

--

Go to Diagnostic System Check - Body Control System

System OK