Buick Regal: DTC B3884
Diagnostic Instructions
- Perform the Diagnostic System Check - Vehicle prior to using this
diagnostic procedure.
- Review Strategy Based Diagnosis for an overview of the diagnostic
approach.
- Diagnostic Procedure Instructions provides an overview of each
diagnostic category.
DTC Descriptors
DTC B3884 01
Center High Mounted Brake Lamp Circuit Short to Battery
DTC B3884 02
Center High Mounted Brake Lamp Circuit Short to Ground
DTC B3884 04
Center High Mounted Brake Lamp Circuit Open
Diagnostic Fault Information
1. Stop Lamps Malfunction
Circuit/System Description
The brake pedal position sensor is used to sense the action of the driver
application of the brake pedal.
The brake pedal position sensor provides an analog voltage signal that will
increase as the brake pedal is
applied. The body control module (BCM) provides a low reference signal and a 5 V
reference voltage to
the brake pedal position sensor. When the variable signal reaches a voltage
threshold indicating the
brakes have been applied, the BCM will apply battery voltage to the right and
left stop lamp control
circuits, engine control module (ECM), and center high mounted stop lamp control
circuit.
Conditions for Running the DTC
- Battery voltage must be between 9 - 16 V.
- Brakes APPLIED.
Conditions for Setting the DTC
DTC B3884 01
The BCM detects a short to voltage in the center high mounted stop lamp
control circuit.
DTC B3884 02
The BCM detects a short to ground in the center high mounted stop lamp
control circuit.
DTC B3884 04
The BCM detects an open/high resistance in the center high mounted stop lamp
control circuit.
Actions Taken When the DTC Sets
The BCM will not illuminate the center high mounted stop lamp.
Conditions for Clearing the DTC
- The condition responsible for setting the DTC no longer exists.
- A history DTC will clear once 100 malfunction-free ignition cycles have
occurred.
Reference Information
Schematic Reference
Exterior Lights Wiring Schematics
Connector End View Reference
COMPONENT CONNECTOR END VIEWS - INDEX
Description and Operation
Exterior Lighting Systems Description and Operation
Electrical Information Reference
- Circuit Testing
- Connector Repairs
- Testing for Intermittent Conditions and Poor Connections
- Wiring Repairs
Scan Tool Reference
Control Module References
Circuit/System Testing
1. Ignition OFF, exterior lamps OFF, trunk latch latched, disconnect the
harness connector at the E6
Center High Mounted Stop Lamp. It may take up to 2 min for all vehicle systems
to power down.
2. Test for less than 5 Ω between the ground circuit terminal 1 and ground.
- Ignition OFF.
- Test for less than 2 Ω in the ground circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, repair the open/high resistance in the ground
connection.
- Go to next step: If less than 5 Ω
3. Connect a test lamp between the control circuit terminal 2 and ground,
ignition ON.
4. Verify the test lamp turns ON and OFF when commanding the Center Brake Lamp
ON and OFF
with a scan tool.
- If the test lamp is always OFF
- Ignition OFF, disconnect the X4 harness connector at the K9 Body Control
Module.
- Test for infinite resistance between the control circuit and ground.
- If less than infinite resistance, repair the short to ground on the
circuit.
- Go to next step: If infinite resistance
- Test for less than 2 Ω in the control circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K9 Body Control Module.
- If the test lamp is always ON
- Ignition OFF, disconnect the X4 harness connector at the K9 Body Control
Module, ignition
ON.
- Test for less than 1 V between the control circuit terminal and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V, replace the K9 Body Control Module.
- Go to next step: If the test lamp turns ON and OFF
5. Test or replace the E6 Center High Mounted Stop Lamp.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
- High Mount Stop Lamp Replacement (Wagon) High Mount Stop Lamp
Replacement
(Hatchback)
- Control Module References for BCM replacement, programming, and setup
READ NEXT:
Diagnostic Instructions
Perform the Diagnostic System Check - Vehicle prior to using this
diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic
approach.
Diag
Diagnostic Instructions
Perform the Diagnostic System Check - Vehicle prior to using this
diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic
approach.
Diag
Diagnostic Instructions
Perform the Diagnostic System Check - Vehicle prior to using this
diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic
approach.
Diag
SEE MORE:
Diagnostic Instructions
Perform the Diagnostic System Check - Vehicle prior to using this
diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic
approach.
Diagnostic Procedure Instructions provides an overview of each
diagnostic category.
DTC Descriptor
DT
Preliminary Procedure
Radiator Replacement (2.0L LTG) or Radiator Replacement (3.6L LGX).
Radiator Lower Bracket
Procedure
Depress the locking tab on the bracket to remove.
RADIATOR LOWER BRACKET REPLACEMENT - RIGHT SIDE
Preliminary Procedure
Radiator Replacement (2.0L LTG) or Radiator Rep