GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2006 🢒 LaCrosse 🢒 Restraints 🢒 SIR 🢒 DTC B3445

Circuit Description

The body control module (BCM) supplies battery positive voltage to the center high-mounted stop lamp (CHMSL), powertrain control module (PCM), engine control module (ECM), and antilock brake system (ABS) module through the stop lamp supply voltage circuits when the brakes are applied.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC B3445 Stop Lamp Circuit

Conditions for Running the DTC

The battery voltage must be between 9-16 volts.

Conditions for Setting the DTC

DTC B3445 will set when the BCM detect an open or short to ground in the stop lamp supply voltage circuits.

Action Taken When the DTC Sets

The CHMSL will not operate.

Conditions for Clearing the MIL/DTC
    • This DTC will clear on current status after the condition for setting the fault 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

Perform a visual inspection for loose or poor connections at all related components. Refer to Testing for Intermittent Conditions and Poor Connections .

Step

Action

Yes

No

Schematic Reference: Exterior Lights Schematics

Connector End View Reference: Master Electrical Component List

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2
  1. Turn the ignition to the ON position.
  2. Apply the brake pedal.

Does the center high-mounted stop lamp (CHMSL) illuminate?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3
  1. Turn the ignition to the OFF position.
  2. Disconnect the CHMSL.
  3. Using a test lamp connected to battery positive voltage, probe the stop lamp voltage supply circuit.

Does the test lamp illuminate?

Go to Step 4

Go to Step 5

4

Test for a short to ground in the stop lamp voltage supply circuits. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 7

Go to Step 6

5

Test for a poor connection or an open in the stop lamp voltage supply circuit. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 7

Go to Step 6

6

Replace the body control module (BCM). Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 7

--

7
  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