Buick Regal: DTC B1287
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 Descriptors
DTC B1287 01
Amplifier Control Signal Circuit Short to Battery
DTC B1287 02
Amplifier Control Signal Circuit Short to Ground
DTC B1287 04
Amplifier Control Signal Circuit Open
Diagnostic Fault Information
Circuit/System Description
The radio amplifier control circuit provides varying pulse width modulated (PWM)
signals to control
overall muting of the amplifier. The PWM signals are varying duty cycle
percentages ranging from 0 -
100 percent. A low duty cycle un-mutes all amplifier channels and a high duty
cycle mutes all amplifier
channels. The amplifier control circuit will measure less than 1 V when the mute
function is OFF, and
approximately 8 V when at full mute. The radio monitors the amp control circuit
for faults.
Conditions for Running the DTC
- The radio is on.
- The system voltage is 9 - 16 V.
- The radio performs the test once during wakeup.
Conditions for Setting the DTC
The radio detects a fault on the amplifier control circuit 400 ms after radio
activates the remote enable
circuit.
Action Taken When the DTC Sets
Radio sets the DTC and continues to output correct state.
Conditions for Clearing the DTC
- The condition must no longer be present.
- A history DTC clears after 50 malfunction-free ignition cycles.
Reference Information
Schematic Reference
Radio/Navigation System Wiring Schematics (IOB) , Radio/Navigation System
Wiring Schematics
(IOR) or Radio/Navigation System Wiring Schematics (IO5/IO6) , or
Radio/Navigation System
Wiring Schematics (IOS/IOT).
Connector End View Reference
Component Connector End View Index
Description and Operation
Radio/Audio System Description and Operation (IO6) , Radio/Audio System
Description and Operation (IOB) , or Radio/Audio System Description and
Operation (IOS/IOT/IOU).
Electrical Information Reference
- Refer to Circuit Testing
- Refer to Connector Repairs
- Refer to Testing for Intermittent Conditions and Poor Connections
- Refer to Wiring Repairs
Scan Tool Reference
Control Module References for scan tool information.
Circuit/System Testing
NOTE: To prevent misdiagnosis, the door chime must be OFF during
testing. Ensure the driver door latch is closed during testing.
1. Ignition OFF/vehicle OFF, disconnect the X1 harness connector at the T3
Amplifier. Ignition
ON/vehicle in Service Mode, A11 Radio ON, mute ON.
2. Test for 7.5 - 8.5 V between the control circuit terminal 3 and ground.
- Ignition OFF/vehicle OFF, disconnect the X1 harness connector at the A11
Radio. Ignition
ON/vehicle in Service Mode.
- Test for less than 1 V between the control circuit and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V, replace the A11 Radio.
- Ignition OFF/vehicle OFF, disconnect the X1 harness connector at the A11
Radio.
- 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 A11 Radio.
- Go to next step: If between 7.5 - 8.5 V
3. A11 Radio ON, mute OFF.
4. Test for less than 1 V between the control circuit terminal 3 and ground.
Replace the A11 Radio.
- Go to next step: If less than 1 V
5. Test or replace the T3 Amplifier.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
Control Module References for radio and amplifier 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.
Refe
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.
Refe
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.
Refe
SEE MORE:
NOTE: The following steps must be completed before using the symptom
tables.
1. Perform the Brake System Vehicle Road Test before using the hydraulic
brake symptom tables in
order to duplicate the customer's concern.
2. Review the system operation in order to familiarize yourself with the system
SEAT BELT SYSTEM DESCRIPTION AND OPERATION
Seat Belts
Solid Line - Hard Wire I/O
Dash Line - Serial Data
A11 - Radio
B88D - Seat Belt Switch - Driver
B88P - Seat Belt Switch - Passenger
K36 - Inflatable Restraint Sensing and Diagnostic Module
K85 - Passenger Presence Detection Module
P16 - Instrume