GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2003 🢒 Corvette 🢒 Body and Accessories 🢒 Doors 🢒 DTC B2236-B2239

Circuit Description

The driver or passenger door switch signal circuits provide inputs to the driver door module (DDM) or passenger door module (PDM) when a door lock switch is activated to the LOCK or UNLOCK position. These inputs allow the door module to detect a door LOCK or UNLOCK request. The door modules provide power and ground to the door lock switches. When a door lock switch is activated to the LOCK or UNLOCK position, ground is supplied through the door lock switch to the signal circuit, which is pulled low. When the door module detects low voltage on the signal circuit, it will command the door latches to LOCK or UNLOCK. If the driver door switch is activated, the DDM will LOCK or UNLOCK the driver door latch and also send a message on the serial data line to the PDM to LOCK or UNLOCK the passenger door latch. If the passenger door switch is activated, the PDM will LOCK or UNLOCK the passenger door latch and also send a message on the serial data line to the DDM to LOCK or UNLOCK the driver door latch. The door modules monitor the signal circuits to determine how long the ground has been applied. If the door module detects that a ground is applied for greater than 20 seconds, a DTC is set.

Conditions for Setting the DTC
    • The DDM or PDM detects a short to ground on a door lock switch signal circuit.
    • Condition must be present for greater than 20 seconds.

Action Taken When the DTC Sets
    • Stores a history DTC B2236, B2237, B2238 or B2239 in DDM or PDM memory.
    • This DTC can only be set as a history code even if the malfunction is current.
    • No driver warning message will be displayed for this DTC.

Conditions for Clearing the DTC

The DDM or PDM no longer detects a short to ground on a door lock switch signal circuit for greater than 20 seconds, and:

    • The DTC is cleared using the IPC clearing feature, or
    • The DTC is cleared using a scan tool.

Diagnostic Aids
    • The following conditions may cause an intermittent malfunction:
       - There is an intermittent short to ground in a door lock switch signal circuit.
       - A door lock switch is shorted to ground internally or is sticking.
       - A door lock switch was pressed for longer than 20 seconds.
    • If the DTC does not reset after the code is cleared, then the problem may be intermittent. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Test Description

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

  1. Tests for the normal state of the door lock/unlock switch using a scan tool. The scan tool will display the normal state as Inactive, and Active when the switch is activated.

    2.

  2. Tests if the DDM or PDM is able to detect a change in a door lock/unlock switch state. The scan tool will display the normal state as Inactive, and Active when the switch is activated.

    3.

  3. Tests for a stuck or shorted door lock/unlock switch. If a door lock/unlock switch is stuck or shorted, the state will change from Active to Inactive when a door lock/unlock switch is disconnected.

    4.

  4. Tests for a short to ground in a door lock/unlock switch signal circuit.

Step

Action

Yes

No

Schematic Reference: Door Control Module 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 appropriate door lock/unlock switch parameter in the appropriate door control module Inputs data list.

Does the scan tool display Inactive?

Go to Step 3

Go to Step 4

3

  1. Activate the appropriate door lock/unlock switch.
  2. With a scan tool, observe the appropriate door lock/unlock switch parameter in the appropriate door control module Inputs data list.

Does the door lock/unlock switch parameter change state?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 4

4

  1. Turn OFF the ignition.
  2. Disconnect the appropriate door switch.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, observe the appropriate door lock/unlock switch parameter in the appropriate door control module Inputs data list.

Does the scan tool display Inactive?

Go to Step 7

Go to Step 5

5

Test the appropriate 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 10

Go to Step 6

6

Inspect for poor connections at the harness connector of the appropriate door 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 8

7

Inspect for poor connections at the harness connector of the appropriate door 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 10

Go to Step 9

8

Replace the appropriate door module. Refer to Door Control Module Replacement .

Did you complete the replacement?

Go to Step 10

--

9

Replace the appropriate door switch. Refer to Front Door Switch Replacement .

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