GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2002 🢒 Impala 🢒 Body and Accessories 🢒 Doors 🢒 DTC B3272

Circuit Description

The door lock switches provide a direct ground input to the body control module (BCM) when one of the switches is activated to the Unlock position, or an input path to ground through a 470ohms resistor when one of the switches is activated to the Lock position. These inputs are used by the BCM to control the output to the door lock actuators.

Conditions for Setting the DTC

The BCM detects a short to ground in the driver door lock switch unlock signal circuit for greater than 60 seconds.

Action Taken When the DTC Sets
    • The BCM stores DTC B3272 in memory.
    • The BCM disables all output operations associated with the input.

Conditions for Clearing the DTC
    • A current DTC B3272 is cleared when the BCM no longer detects a short to ground in the driver door lock switch unlock signal circuit for greater than 60 seconds.
    • A history DTC B3272 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 the DTC B3272 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 ground in the driver door lock switch unlock signal circuit.
       - A door lock switch intermittently shorted to ground.
       - A door lock switch that was held in the Lock or Unlock position for greater than 60 seconds.
       - The BCM intermittently shorted to ground internally.

Test Description

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

  1. Tests to determine if the short to ground in the driver door lock switch unlock signal circuit is present.

    2.

  2. Tests to determine if the short to ground in the driver door lock switch unlock signal circuit is intermittent.

    3.

  3. Tests to determine if the driver door lock switch is shorted to ground.

    4.

  4. Tests to determine if the front passenger door lock switch is shorted to ground.

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 Diagnostic System Check - Door Systems

2

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, observe the door unlock switch parameter in the Body Control Module data list.

Does the scan tool display Inactive?

Go to Step 3

Go to Step 4

3

  1. Activate a door lock switch.
  2. With a scan tool, observe the door unlock switch parameter in the Body Control Module data list.

Does the door unlock switch parameter change state?

Go to Diagnostic Aids

Go to Step 7

4

  1. Turn OFF the ignition.
  2. Disconnect the driver door lock switch.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, observe the door unlock switch parameter in the Body Control Module data list.

Does the scan tool display Inactive?

Go to Step 8

Go to Step 5

5

  1. Turn OFF the ignition.
  2. Connect the driver door lock switch.
  3. Disconnect the front passenger door lock switch.
  4. Turn ON the ignition, with the engine OFF.
  5. With a scan tool, observe the door unlock switch parameter in the Body Control Module data list.

Does the scan tool display Inactive?

Go to Step 8

Go to Step 6

6

Test the driver door lock switch unlock signal circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 11

Go to Step 7

7

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 11

Go to Step 9

8

Inspect for poor connections at the harness connector of the appropriate door lock switch. 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 11

Go to Step 10

9
  1. Perform the set up procedure for the body control module. Refer to Body Control Module (BCM) Programming/RPO Configuration in Body Control System.
  2. Replace the body control module. Refer to Body Control Module Replacement in Body Control System.

Did you complete the replacement?

Go to Step 11

--

10

Replace the appropriate door lock switch. Refer to Door Lock Switch Replacement .

Did you complete the replacement?

Go to Step 11

--

11
  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