GM Service Manual Online
For 1990-2009 cars only

For wiring diagrams, refer to

Cell 51: DTC B3137, B3138, B3147, B3148 -- Power Door Locks


Object Number: 357908  Size: FS
Body Control Module Components
Body Control System Circuit Description
Power Distribution Schematics
Door Lock/Indicator Schematics
Release Systems Schematics
Handling ESD Sensitive Parts Notice
in Body Control System Schematics.

Circuit Description

The body control module (BCM) monitors and supplies an output voltage on CKT 195 in order to lock the doors. When the BCM receives a lock signal from the remote control door lock receiver to lock the doors, the BCM supplies voltage to the lock relay and locks the door. If CKT 195 is shorted to battery for more than 184 seconds, the BCM will set DTC B3138 as a current code.

Conditions for Setting the DTC

    • CKT 195 is shorted to battery voltage for more than 184 seconds.
    • The system voltage is between 9.0-16.0 volts.
    • The above conditions exist for 184 seconds.

Action Taken When the DTC Sets

The power door lock system will not function with the remote control door lock system or either of the power door lock switches.

Conditions for Clearing the MIL/DTC

    • A current DTC will clear immediately after the short to battery voltage is corrected.
    • A history DTC will clear after 100 consecutive ignition cycles without a fault present.
    • History and current DTCs can be cleared using a scan tool.

Diagnostic Aids

    • Always diagnose the first DTC that is listed on the scan tool.
    • Verify that the scan tool displays DTC B3138 as a current code before you perform diagnostics.
    • Inspect for loose or poor connections at all of the of the related components.
    • Refer to Wiring Systems for intermittent or poor connections.

Test Description

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

  1. This step determines if the LF door lock switch is shorted to battery voltage.

  2. This step determines if the RF door lock switch is shorted to battery voltage.

  3. This step determines if one of the following conditions exists:

  4. • CKT 195 is shorted to battery voltage.
    • The BCM is defective.

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. Use a scan tool in order to monitor the current DTCs.
  2. Disconnect the LF door lock switch.

Does the scan tool display B3138 as a current code?

--

Go to Step 3

Go to Step 6

3

  1. Use a scan tool in order to monitor the current DTCs.
  2. Disconnect the RT door lock switch.

Does the scan tool display B3138 as a current code?

--

Go to Step 4

Go to Step 7

4

  1. Disconnect the BCM connector C1 (BRN). Remove the comb from the connector.
  2. Use a J 39200 in order to backprobe between CKT 195 (LT BLU) cavity A4 and ground.

Does the J 39200 display battery voltage?

--

Go to Step 5

Go to Step 8

5

Locate and repair the short to battery voltage in CKT 195 (LT GRN) between the BCM and one of the following components:

    • The LOCK relay
    • The LF and RF door lock switches
    • The rear gate switch (on Utility)

Is the repair complete?

--

Go to Step 9

--

6

Replace the LF door lock switch.

Is the repair complete?

--

Go to Step 9

--

7

Replace the RT door lock switch.

Is the repair complete?

--

Go to Step 9

--

8

  1. Replace the BCM.
  2. Program the correct calibrations into the BCM.
  3. Perform the learn procedure.

Is the repair complete?

--

Go to Step 9

--

9

  1. Connect all of the connectors.
  2. Clear the DTCs.

Is the repair complete?

--

Go to Diagnostic System Check - Body Control System

--