Buick Regal: DTC B263A
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 B263A 02
Exterior Illumination Lamp Circuit Short to Ground
DTC B263A 04
Exterior Illumination Lamp Circuit Open
Diagnostic Fault Information
1. Exterior Courtesy Lamps Malfunction
Circuit/System Description
The body control module (BCM) supplies battery voltage to the exterior
courtesy LED lighting located
under each outside rearview mirror for approach lighting. When the keyless entry
transmitter is operated
to the lock/unlock functions the exterior door handles LED and the LED lighting
located under each
outside rearview mirror for approach lighting are commanded ON.
Conditions for Running the DTC
- Battery voltage must be between 9 - 16 V.
- Park lamps ON.
Conditions for Setting the DTC
DTC B263A 02
The BCM detects a short to ground in the exterior courtesy lamps control
circuit terminal 8 X7.
DTC B263A 04
The BCM detects an open/high resistance in the exterior courtesy lamps
control circuit terminal 8 X7.
Actions Taken When the DTC Sets
The BCM will disable the exterior courtesy lamps control circuit.
Conditions for Clearing the DTC
- The condition responsible for setting the DTC no longer exists.
- A history DTC will clear once 100 consecutive 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 for scan tool information.
Circuit/System Testing
1. Ignition OFF, all doors closed, all accessories OFF, disconnect the
harness connectors at the A9A
Outside Rearview Mirror - Driver and the A9B Outside Rearview Mirror -
Passenger. It may take
up to 2 min for all vehicle systems to power down.
2. Test for less than 15 Ω between the appropriate ground circuit terminal 4 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 15 Ω
3. Connect a test lamp between the control circuit terminal 17 and ground,
ignition ON.
4. Verify the test lamp turns ON and OFF when commanding the Outside Rear View
Mirror
Courtesy Lamp ON and OFF with a scan tool.
- If the test lamp is always OFF
- Ignition OFF, disconnect the X7 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 X7 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 appropriate E66 Outside Rearview Mirror Lamps
Assembly.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
Control Module References for BCM replacement, programming, and setup.
DTC B2645
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 B2645 03
Ambient Light Sensor Circuit Low Voltage
DTC B2645 07
Ambient Light Sensor Circuit High Voltage
Diagnostic Fault Information
1. Daytime Running Lamps Malfunction
Circuit/System Description
The ambient light sensor is used to monitor outside lighting conditions. The
body control module
(BCM) provides a 5 V reference signal to the ambient light sensor. Depending on
outside lighting
conditions, the ambient light sensor provides a voltage signal to the BCM that
will vary between 0.2 and
4.9 V. The BCM monitors the ambient light sensor signal circuit to determine if
outside lighting
conditions are correct for either daytime running lamps or automatic headlamp
system control when the
headlamp switch is in the AUTO position. In daylight conditions, the BCM will
command the daytime
running lamps ON by applying voltage to the daytime running lamps control
circuits illuminating the
daytime running lamps. Any function or condition that turns on the headlamps
will cancel daytime
running lamps operation.
Conditions for Running the DTC
Battery voltage must be between 9-16 V.
Conditions for Setting the DTC
DTC B2645 03
The BCM detects a short to ground in the ambient light sensor signal circuit.
DTC B2645 07
- The BCM detects a short to voltage or an open/high resistance in the
ambient light sensor signal
circuit.
- The BCM detects an open/high resistance in the ambient light sensor low
reference circuit.
Actions Taken When the DTC Sets
- Automatic headlamp system and daytime running lamps are inoperative.
- The BCM defaults to low light status and commands the low beam headlamps
ON.
Conditions for Clearing the DTC
- The condition responsible for setting the DTC no longer exists.
- A history DTC will clear once 100 consecutive malfunction-free ignition
cycles have occurred.
Reference Information
Schematic Reference
Headlights/Daytime Running Lights (DRL) 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 for scan tool information
Circuit/System Testing
1. Ignition OFF, scan tool disconnected, all doors closed, all accessories
OFF, open and close drivers
door, disconnect the harness connector at the B10B Ambient Light/Sunload Sensor.
It may take up
to 2 min for all vehicle systems to power down.
2. Test for less than 15 Ω between the low reference circuit terminal 6 and
ground.
- Ignition OFF, disconnect the X2 harness connector at the K33 HVAC
Control Module.
- Test for less than 2 Ω in the low reference circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K33 HVAC Control Module.
- Go to next step: If less than 15 Ω
3. Ignition ON.
4. Verify the scan tool Ambient Light Sensor parameter is greater than 4.65 V.
- Ignition OFF, disconnect the X2 harness connector at the K9 Body Control
Module.
- Test for infinite resistance between the signal circuit terminal 3 and
ground.
- If less than infinite resistance, repair the short to ground on the
circuit.
- If infinite resistance, replace the K9 Body Control Module.
- Go to next step: If greater than 4.65 V
5. Install a 3 A fused jumper wire between the signal circuit terminal 3 and
the low reference circuit
terminal 6.
6. Verify the scan tool Ambient Light Sensor parameter is less than 0.196 V.
- Ignition OFF, disconnect the X2 harness connector at the K9 Body Control
Module, ignition
ON.
- Test for less than 1 V between the signal circuit terminal 3 and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- Go to next step: If less than 1 V
- Test for less than 2 Ω in the signal 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.
- Go to next step: If less than 0.196 V
7. Test or replace the B10B Ambient Light/Sunload Sensor.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
- Sun Load Temperature and Headlamp Automatic Control Ambient Light Sensor
Replacement
- 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.
Refer to Diagnostic Procedure Instructions for an overview of each
diagnostic category.
DTC Descripto
SPECIFICATIONS
FASTENER SPECIFICATIONS
Single Use Non-Threaded Fasteners/Components
NOTE:
All fasteners/components listed in this table MUST BE DISCARDED and replaced
with NEW after removal.
Application
Transmission Fluid Cooler Line Seal
Transmission Fluid Cooler Pipe Fitting Retainer
Reusable Thre