GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2000 🢒 LeSabre 🢒 Body and Accessories 🢒 Doors 🢒 DTC B3142 LF Unlock Switch Circuit Low

Object Number: 428890 Size: MF
LH Front Door
Handling ESD Sensitive Parts Notice
Front Door Dimming
G200 (2 of 2)
Data Link Connector Schematics
Simple Bus Interface

Circuit Description

The switch that failed and generated this diagnostic trouble code (DTC) is wired to the driver door switch assembly (DDSA). The DDSA includes the switch state in the message it sends to the driver door module (DDM). The DDM sends the switch message to the rear integration module (RIM), which is the "master" of all lock operations, as a Class 2 message. The RIM sends its OK to the DDM. If the OK message is received, the DDM sends the required signal to all other door modules via the simple bus interface (SBI) message system.

Conditions for Running the DTC

The DDM must be powered and can not have B1327-Battery Voltage Low or B1328-Battery Voltage High set for this DTC to set.

Conditions for Setting the DTC

If the DDM receives the message that the circuit is closed for more than 255 continuous seconds (4.25 minutes), the DDM sets this DTC.

Action Taken When the DTC Sets

The DDM ignores any message from this switch and prevents lock movement from the driver door interior switches. The DDM will respond to other lock switch message.

Conditions for Clearing the DTC

The DDM clears this DTC when the switch message is no longer received.

Test Description

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

  1. Checks the existing state of the driver door lock switch by using the current state of the input parameter.

Step

Action

Yes

No

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 leaving the engine OFF.
  3. Observe the Driver Door Lock Sw. parameter in the Driver Door Module data list using the scan tool.

Does the scan tool display Idle?

Go to Step 3

Go to Step 4

3
  1. Activate the driver door lock switch.
  2. Observe the Driver Door Lock Sw. parameter using the scan tool.

Does the Driver Door Lock Sw. parameter change state?

Go to Step 10

Go to Step 4

4
  1. Turn OFF the ignition.
  2. Disconnect the driver door lock switch.
  3. Turn ON the ignition leaving the engine OFF.
  4. Observe the Driver Door Lock Sw. parameter using the scan tool.

Does the scan tool indicate the Idle state?

Go to Step 7

Go to Step 5

5

Test the driver lock switch unlock input circuit for a short. 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/terminal tension at the driver door switch assembly harness connector. 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/terminal tension at the driver door lock switch harness connector. 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 driver door switch assembly. Refer to Front Door Switch Replacement .

Did you complete the replacement?

Go to Step 10

--

9

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

Did you complete the replacement?

Go to Step 10

--

10
  1. Clear the DTCs using the scan tool.
  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