Buick Regal: DTC B1025-B1135 (UQ3 with 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
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
- 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
replicates the high level audio signals from the radio to the speakers. If
the module malfunctions,
all the speakers may become inop.
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, 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 but not all.
Refer to Circuit/System Testing One Speaker.
- If audio is Inoperative from all speakers.
Refer to Circuit/System Testing All Speakers.
- Go to next step: If clear audio is heard from all speakers.
3. All OK.
Circuit/System Testing
One Speaker
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, 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, disconnect the appropriate harness connector at the K108
Active Noise
Cancellation Module / T3 Audio Amplifier.
- Test for infinite resistance between the appropriate 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 K108 Active Noise Cancellation Module
/ T3 Audio
Amplifier.
- Ignition OFF, disconnect the appropriate harness connector at the K108
Active Noise
Cancellation Module / T3 Audio Amplifier.
- Ignition ON, A11 Radio ON, mute OFF. Test for less than 1 V between the
appropriate
signal circuit and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V, replace the K108 Active Noise Cancellation Module
/ T3 Audio
Amplifier.
- Go to next step: If between 5 - 7 V
3. Ignition OFF, disconnect the appropriate harness connector at the K108
Active Noise Cancellation
Module / T3 Audio Amplifier.
4. Ignition ON, A11 Radio ON, mute OFF. Test for 5 - 7 V between each
appropriate audio signal
circuit from the A11 Radio and Ground.
- Ignition 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, disconnect the appropriate speaker harness connector at
the A11 Radio.
Ignition ON.
- 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
5. Test or replace the P19 Speaker.
All Speakers
1. Ignition OFF, disconnect the X1 harness connector at the K108 Active Noise
Cancellation Module
/ T3 Audio Amplifier.
2. Test for less than 10 Ω between the ground circuit terminal 8 and ground.
- 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 10 Ω
3. Verify that a test lamp illuminates between the B+ circuit terminal 4 and
ground.
- If the test lamp does not illuminate
- Remove the test lamp.
- Test for less than 2 Ω in the B+ circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- Go to next step: If the test lamp illuminates
4. Ignition ON, A11 Radio ON.
5. Verify that a test lamp illuminates between the control circuit terminal 3
and ground.
- If the test lamp does not illuminate
- Ignition 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 the test lamp illuminates
6. Test for 5 - 7 V between any audio signal circuit from the A11 Radio and
Ground.
Test or replace the A11 Radio.
- Go to next step: If between 5 - 7 V
7. Test or replace the K108 Active Noise Cancellation Module / T3 Audio
Amplifier.
Repair Instructions
- Refer to Speaker Replacement Reference
- Refer to Control Module References for radio and amplifier replacement,
programming, and
setup.
- Perform the Diagnostic Repair Verification after completing the repair.
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 prior to using this diagnostic
procedure: Diagnostic
System Check - Vehicle
Review the description of Strategy Based Diagnosis: Strate
SEE MORE:
SPECIFICATIONS
FASTENER SPECIFICATIONS
Reusable Threaded Fastener Tightening Specifications
NOTE:
All fasteners listed in this table can be reused after removal.
SCHEMATIC WIRING DIAGRAMS
INSIDE REARVIEW MIRROR WIRING SCHEMATICS
Auto-Dimming Mirror (DD8)
OUTSIDE REARVIEW MIRROR WIRING SCHEMATICS
D
Obstruction of the GPS can
occur in a large city with tall
buildings; in parking garages;
around airports; in tunnels and
underpasses; or in an area with
very dense trees. If GPS signals
are not available, the OnStar
system should still operate to
call OnStar. However, OnStar
could have d