Buick Regal: DTC B1025-B1135 (UQ3 without NKC)
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 B1025
Left Front Audio Output Circuit
DTC B1035
Right Front Audio Output Circuit
DTC B1045
Left Rear Audio Output Circuit
DTC B1055
Right Rear Audio Output Circuit
For symptom byte information refer to Symptom Byte List.
Diagnostic Fault Information
1. No or reduced audio from speaker (s) on the affected audio circuit.
2. Noticeable audio distortion may be present.
Circuit/System Description
Each of the audio output channel circuits (+) and (-), at the radio have a DC
bias voltage that is
approximately one half of battery voltage. When using a DMM, each of the audio
output channel
circuits will measure approximately 6.5 V DC. The audio being played on the
system is produced by a
varying AC voltage that is centered around the DC bias voltage on the same
circuit. The AC voltage is
what causes the speaker cone to move and produce sound. The frequency (Hz) of
the AC voltage signal
is directly related to the frequency of the input (audio source playing) to the
audio system. Both the DC
bias voltage and the AC voltage signals are needed for the audio system to
properly produce sound.
Conditions for Running the DTC
- Vehicle in Service Mode/Ignition is ON or in the ACC position
- The system voltage is 9-16 V
- The test is run once during radio wake up
Conditions for Setting the DTC
B1025 01, B1035 01, B1045 01, B1055 01
The radio detects a short to voltage on the specified audio (+) or (-)
circuit.
B1025 02, B1035 02, B1045 02, B1055 02
The radio detects a short to ground on the specified audio (+) or (-)
circuit.
B1025 04, B1035 04, B1045 04, B1055 04
The radio detects an open on the specified audio (+) or (-) circuit.
Action Taken When the DTC Sets
The radio continues to send the output signal to the speaker signal circuit
with the current fault.
Conditions for Clearing the DTC
- A current DTC clears when the conditions for setting the DTC are no
longer present and the
ignition has been cycled from OFF to ON.
- A history DTC clears after 50 malfunction-free ignition cycles.
Diagnostic Aids
- Improper speaker mounting or loose trim may cause an audible buzz or
distortion. Inspect the
appropriate speaker and the surrounding interior trim for proper and secure
mounting.
- The EL-50334-6 Audio System Diagnostic CD contains audio tracks that can
be used to duplicate
and isolate such concerns. Tracks 11 and 12 contain audio sweep tones for
testing for speaker and
grill rattles.
- The test tones on the CD may be copied to a USB drive or other device to
use during testing.
- If the speaker or surrounding interior trim is found to be loose or
improperly secured, correctly
secure the item.
- If equipped with an Active Noise Cancellation system that utilizes an
ANC module, the module
acts as a pass-through for the high level audio signals from the radio to
the speakers.
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 Verification
1. Ignition ON/vehicle in Service Mode, A11 Radio ON, mute OFF.
2. Verify clear audio is heard from each speaker, adjusting fade and balance
controls to test each
speaker individually.
- If audio is inoperative from one or more speakers, or the audio
emitted is not clear.
Refer to Circuit/System Testing.
- Go to next step: If clear audio is heard from all speakers.
3. All OK.
Circuit/System Testing
NOTE: Some circuits supply audio signals to more than one speaker. It
may
be necessary to disconnect all speakers on the affected audio
circuit when performing circuit tests.
1. Ignition OFF/vehicle OFF, disconnect the harness connector at the
appropriate P19 Speaker.
Ignition ON, A11 Radio ON, mute OFF.
2. Test for 5 - 7 V between each audio signal circuit terminal 1 and terminal 2
and ground.
- Ignition OFF/vehicle OFF, disconnect the appropriate speaker harness
connector at the A11
Radio.
- Test for infinite resistance between the signal circuits 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 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 A11 Radio.
- Ignition OFF/vehicle OFF, disconnect the appropriate speaker harness
connector at the A11
Radio. Ignition ON/vehicle in Service Mode.
- Test for less than 1 V between the signal 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.
- Go to next step: If between 5 - 7 V
3. Test or replace the P19 Speaker.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
- Speaker Replacement Reference
- Refer to Control Module References for radio 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:
If equipped, memory seats allow two
drivers to save and recall their
unique seat positions for driving the
vehicle, and a shared exit position
for getting out of the vehicle. Other
feature positions may also be
saved, such as power mirrors and
power steering wheel, if equipped.
Memory positions ar
Special Tools
GE-26568 Coolant and Battery Tester
WARNING: With a pressurized cooling system, the coolant temperature in
the radiator
can be considerably higher than the boiling point of the solution at
atmospheric pressure. Removal of the surge tank cap, while the cooling
system is hot and under h