GM Service Manual Online
For 1990-2009 cars only

Object Number: 308618  Size: SF
Body Control Module Components
Body Control System Schematics
Power Distribution Schematics
Power Distribution Schematics
Handling Electrostatic Discharge Sensitive Parts Notice

Circuit Description

Pressing lock or unlock on either door lock switch sends a ground signal to the BCM through circuit 780 or 781 respectively. This action causes the BCM to supply voltage from circuit 1540 to either circuit 294 or 295 for 350 (+/- 35) ms, energizing the door actuators and unlocking (except driver's door) or locking the vehicle doors.

Conditions for Setting the DTC

    • The BCM detects an open in circuit 1540.
    • All conditions must be present for more than 0.3 seconds.

Action Taken When the DTC Sets

The BCM stores DTC B0807 in memory.

Conditions for Clearing the DTC

    • The BCM detects B+ in circuit 1540 when trying to lock or unlock the doors.
    • A history DTC will clear after 100 consecutive ignition cycles if the condition for the malfunction is no longer present.
    • Using a scan tool.

Diagnostic Aids

    • If the DTC is a history DTC, the problem may be intermittent. Try performing the tests shown while moving wiring and connectors, this can often cause the malfunction to reappear.
    • DTC P1626 will set in the Powertrain Control Module (PCM) when the ignition switch is on with the Body Control Module (BCM) disconnected. When BCM diagnostics and repair are completed, refer to Powertrain Control Module Diagnosis in Engine Controls for additional information on PCM related DTCs.

Test Description

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

  1. This step checks for a short to ground in circuits 294, 295 and 1540.

  2. This step checks for a short to ground in circuit 1540.

  3. This step checks for a short to ground in circuit 294.

  4. This step checks for a short to ground in circuit 295.

  5. This step checks for an open in circuit 1540.

  6. This step determines whether the malfunction is intermittent or the BCM is faulty.

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

Check the DOOR LOCKS fuse.

Is the DOOR LOCKS fuse open?

--

Go to Step 3

Go to Step 6

3

  1. Replace the DOOR LOCKS fuse.
  2. Check the DOOR LOCKS fuse again.

Is the DOOR LOCKS fuse open again?

--

Go to Step 8

Go to Step 4

4

  1. Turn the ignition switch off.
  2. Turn the ignition switch on.
  3. Press lock on either door lock switch.
  4. Check the DOOR LOCKS fuse again.

Is the DOOR LOCKS fuse open again?

--

Go to Step 9

Go to Step 5

5

  1. Press unlock on either door lock switch.
  2. Check the DOOR LOCKS fuse again.

Is the DOOR LOCKS fuse open again?

--

Go to Step 10

Go to Step 6

6

  1. Turn the ignition switch off.
  2. Disconnect the Body Control Module (BCM) connector C3.
  3. Using a test lamp, connect between the BCM harness connector C3 terminal J and ground.

Is the test light on?

--

Go to Step 7

Go to Step 11

7

  1. Turn the ignition switch off.
  2. Reinstall connectors/components removed.
  3. Turn the ignition switch on.
  4. Clear BCM DTCs. Refer to Clearing DTCs for more information.
  5. Check for BCM DTCs. Refer to Diagnostic Trouble Code (DTC) Displaying for more information.

Does DTC B0807 reset as a current DTC?

--

Go to Step 12

Go to Step 13

8

Repair short to ground in circuit 1540.

Is the repair complete?

--

Go to Step 14

--

9

Repair short to ground in circuit 295.

Is the repair complete?

--

Go to Step 14

--

10

Repair short to ground in circuit 294.

Is the repair complete?

--

Go to Step 14

--

11

Repair poor connection or open in circuit 1540.

Is the repair complete?

--

Go to Step 14

--

12

    • Check the BCM connector C3 terminal J for poor connection.
    • If connection is OK, then replace the BCM. Refer to Body Control Module Replacement for more information.
    • After replacing the BCM, perform the Setup New BCM procedure. Refer to Body Control Module (BCM) Programming/RPO Configuration for more information.

Is the repair complete?

--

Go to Step 14

--

13

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

--

--

--

14

  1. Turn the ignition switch off.
  2. Reinstall connectors/components removed.
  3. Turn the ignition switch on.
  4. Clear the BCM DTCs. Refer to Clearing DTCs for more information.
  5. Check for the BCM DTCs. Refer to Diagnostic Trouble Code (DTC) Displaying for more information.

Are there any BCM current DTCs set?

--

Go to Diagnostic System Check - Body Control System

System OK