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Chevrolet Silverado / GMC Sierra. Manual - part 2473
Circuit/System Description
When the PRNDL is placed in the REVERSE position, a signal is sent to the body control
module (BCM). The BCM then applies voltage through the backup lamps relay control circuit to
the BACK/UP lamp relay in the underhood fuse block, inside rearview mirror, and rearview
camera module. The BACK/UP lamp relay then illuminates the backup lamps.
Conditions for Running the DTC
The ignition is ON.
The backup lamps must be commanded ON.
Conditions for Setting the DTC
The BCM detects a short to ground on the backup lamp relay control circuit when the backup
lamps are being commanded ON.
Action Taken When the DTC Sets
The backup lamps do not illuminate.
Conditions for Clearing the DTC
The conditions for setting the DTC are no longer present.
A history DTC clears after 100 malfunction-free ignition cycles.
Reference Information
Schematic Reference
Exterior Lights Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Exterior Lighting Systems Description and Operation
Electrical Information Reference
Circuit Testing
2008 Chevrolet Silverado 1500
2008 ACCESSORIES & EQUIPMENT Lighting - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado
Connector Repairs
Testing for Intermittent Conditions and Poor Connections
Wiring Repairs
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
Ignition ON, activate the Backup Lamps output control on the scan tool. The Backup Lamps
parameter in the data list should display On and the backup lamps should illuminate.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector X2 at the BCM.
2. Ignition ON, vehicle in park, verify the backup lamps are not on.
If the backup lamps are on, test the backup lamp relay control circuit terminal 22 for a
short to voltage. If the circuit tests normal replace the underhood fuse block.
3. Install a 10A fused jumper wire between the relay control circuit terminal 22 and battery
voltage. Verify the backup lamps are on.
If the backup lamps are not on, test the backup lamp relay control circuit for an
open/high resistance or short to ground. If the circuit tests normal replace the
underhood fuse block.
4. If all circuits test normal, replace the BCM.
Repair Procedures
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Underhood Electrical Center or Junction Block Replacement
Control Module References for BCM, inside rearview mirror, and rearview camera
module replacement, setup, and programming
DTC B2555
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.
2008 Chevrolet Silverado 1500
2008 ACCESSORIES & EQUIPMENT Lighting - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado
Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptors
DTC B2555 01
Passenger Compartment Lamp Control Circuit Short to Battery
DTC B2555 02
Passenger Compartment Lamp Control Circuit Short to Ground
Diagnostic Fault Information
Circuit/System Description
When the body control module (BCM) signals for courtesy lamp operation, a message is sent over
the GM LAN serial data circuit to the driver door and passenger door switches. The driver door
switch and passenger door switch the applies battery voltage to the left and right courtesy lamp
control circuits illuminating the door courtesy lamps. The driver door and passenger door
switches also provide ground to the lamps.
Conditions for Running the DTC
Battery voltage must be between 9-16 volts.
A message is sent from the BCM over the GM LAN serial data circuit to the driver door and
passenger door switches to active the door courtesy lamps.
Conditions for Setting the DTC
B2555 01
This DTC will set when the driver or passenger door switch detects a short to voltage in the
courtesy lamp control circuit.
Circuit
Short to
Ground
Open/High
Resistance
Short to
Voltage
Signal
Performance
Left Courtesy Lamp Control
Circuit
B2555 02
1
B2555 01
-
Right Courtesy Lamp Control
Circuit
B2555 02
1
B2555 01
-
1. Courtesy Lamps Inoperative
2008 Chevrolet Silverado 1500
2008 ACCESSORIES & EQUIPMENT Lighting - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado
B2555 02
This DTC will set when the driver or passenger door switch detects a short to ground in the
courtesy lamp control circuit.
Action Taken When the DTC Sets
B2555 01
When this DTC is present, the door courtesy lamps will remain illuminated.
B2555 02
When this DTC is present, the door courtesy lamps will be inoperative.
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
Interior Lights Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Interior Lighting Systems Description and Operation
Electrical Information Reference
Circuit Testing
Connector Repairs
Testing for Intermittent Conditions and Poor Connections
Wiring Repairs
2008 Chevrolet Silverado 1500
2008 ACCESSORIES & EQUIPMENT Lighting - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado
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