GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2003 🢒 Monte Carlo 🢒 Body and Accessories 🢒 Doors 🢒 DTC B3128, B3133, or B3138

Circuit Description

The outputs to the door lock actuators are controlled by the body control module (BCM). When the BCM receives a Lock input from a door lock switch or keyless entry transmitter, it applies battery positive voltage to the door lock actuator lock control circuit and a ground to the door lock actuator unlock control and driver door lock actuator unlock control circuits. When the BCM receives an Unlock input from a door lock switch, it applies battery positive voltage to the door lock actuator unlock control and driver door lock actuator unlock control circuits and a ground to the door lock actuator lock control circuit . When the BCM receives an single Unlock input from a keyless entry transmitter, it applies battery positive voltage to the driver door lock actuator unlock control circuit and a ground to the door lock actuator lock control circuit to unlock the driver door. A second Unlock input from the transmitter applies battery positive voltage to the door lock actuator unlock control circuit and a ground to the door lock actuator lock control circuit to unlock the passenger door(s).

Conditions for Setting the DTC

The BCM detects a short to voltage on the door lock actuator lock control circuit, door lock actuator unlock control circuit or driver door lock actuator unlock control circuit for greater than 150 milliseconds.

Action Taken When the DTC Sets
    • The BCM stores DTC B3128, B3133 or B3138 in memory.
    • The BCM disables the output function (Lock or Unlock) associated with the ground side circuit output.

Conditions for Clearing the DTC
    • A current DTC B3128, B3133 or B3138 is cleared when the BCM no longer detects a short to voltage on the door lock actuator lock control circuit, door lock actuator unlock control circuit or driver door lock actuator unlock control circuit for greater than 150 milliseconds
    • A history DTC B3128, B3133 or B3138 is cleared after 100 consecutive ignition cycles with the condition for setting the DTC no longer present.
    • The DTC is cleared using a scan tool.

Diagnostic Aids
    • If DTC B3128, B3133 or B3138 is a history DTC, the fault may be intermittent. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
    • The following conditions may cause an intermittent malfunction to occur:
       - An intermittent short to voltage on the door lock actuator lock control circuit, door lock actuator unlock control circuit or driver door lock actuator unlock control circuit.
       - The body control module (BCM) intermittently shorted to voltage internally

Test Description

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

  1. Tests to determine if the DTC is intermittent.

    2.

  2. Tests to determine if a lock or unlock circuit is malfunctioning.

    3.

  3. Tests to determine if the driver door unlock or all door unlock circuit is malfunctioning.

Step

Action

Yes

No

Schematic Reference: Door Lock/Indicator Schematics

Connector End View Reference: Power Door Systems Connector End Views

1

Did you perform the Door Systems Diagnostic System Check?

Go to Step 2

Go to Symptoms - Doors

2

Are DTCs B3128, B3133 and B3138 Current DTCs?

Go to Step 3

Go to Diagnostic Aids

3

  1. Observe each of the manual door locks at each door.
  2. Activate a door lock switch to the LOCK and UNLOCK positions.

Is the Lock function inoperative?

Go to Step 4

Go to Step 7

4

Is the Lock function inoperative on the driver door?

Go to Step 5

Go to Step 6

5

Test the driver door lock actuator unlock control circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 10

Go to Step 8

6

Test the door lock actuator unlock control circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 10

Go to Step 8

7

Test the door lock actuator lock control circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 10

Go to Step 8

8

Inspect for poor connections at the harness connector of the body control module. 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 10

Go to Step 9

9

Important: Perform the set up procedure for the body control module. Refer to Body Control Module (BCM) Programming/RPO Configuration in Body Control System.

Replace the body control module. Refer to Body Control Module Replacement in Body Control System.

Did you complete the replacement?

Go to Step 10

--

10
  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

Go to Step 2

System OK