GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2009 🢒 Avalanche - 2WD 🢒 Driver Information and Entertainment 🢒 Cellular, Entertainment, and Navigation 🢒 DTC B1025-B1095

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 provide an overview of each diagnostic category.

DTC Descriptors

DTC B1025 01: Audio Output 1 Left Front Circuit Short to Battery

DTC B1025 02: Audio Output 1 Left Front Circuit Short to Ground

DTC B1025 04: Audio Output 1 Left Front Circuit Open

DTC B1035 01: Audio Output 2 Right Front Circuit Short to Battery

DTC B1035 02: Audio Output 2 Right Front Circuit Short to Ground

DTC B1035 04: Audio Output 2 Right Front Circuit Open

DTC B1045 01:  Audio Output 3 Left Rear Circuit Short to Battery

DTC B1045 02:  Audio Output 3 Left Rear Circuit Short to Ground

DTC B1045 04:  Audio Output 3 Left Rear Circuit Open

DTC B1055 01:  Audio Output 4 Right Rear Circuit Short to Battery

DTC B1055 02:  Audio Output 4 Right Rear Circuit Short to Ground

DTC B1055 04:  Audio Output 4 Right Rear Circuit Open

DTC B1065 01:  Audio Output 5 Circuit Short to Battery (Center IP)

DTC B1065 02:  Audio Output 5 Circuit Short to Ground (Center IP)

DTC B1065 04:  Audio Output 5 Circuit Open (Center IP)

DTC B1075 01:  Audio Output 6 Circuit Short to Battery (Subwoofer)

DTC B1075 02:  Audio Output 6 Circuit Short to Ground (Subwoofer)

DTC B1075 04:  Audio Output 6 Circuit Open (Subwoofer)

DTC B1085 01:  Audio Output 7 Circuit Short to Battery (LR D-Pillar)

DTC B1085 02:  Audio Output 7 Circuit Short to Ground (LR D-Pillar)

DTC B1085 04:  Audio Output 7 Circuit Open (LR D-Pillar)

DTC B1095 01:  Audio Output 8 Circuit Short to Battery (RR D-Pillar)

DTC B1095 02:  Audio Output 8 Circuit Short to Ground (RR D-Pillar)

DTC B1095 04:  Audio Output 8 Circuit Open (RR D-Pillar)

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Left Front Speaker Signal Circuits (Front Door and Tweeter)

B1025 02*

B1025 04*

B1025 01*

--

Right Front Speaker Signal Circuits (Front Door and Tweeter)

B1035 02*

B1035 04*

B1035 01*

--

Left Rear Speaker Signal Circuits (Rear Door)

B1045 02*

B1045 04*

B1045 01*

--

Right Rear Speaker Signal Circuits (Rear Door)

B1055 02*

B1055 04*

B1055 01*

--

Front Center Speaker Signal Circuits (Center IP)

B1065 02*

B1065 04*

B1065 01*

--

Subwoofer Low Level Audio Signal Circuits (Center Console)

B1075 02*

B1075 04*

B1075 01*

--

Left Midrange Speaker Signal Circuits (LR D-Pillar)

B1085 02*

B1085 04*

B1085 01*

--

Right Midrange Speaker Signal Circuits (RR D-Pillar)

B1095 02*

B1055 04*

B1095 01*

--

* Noticeable audio distortion possible.

Circuit/System Description

Each of the audio output channel circuits (+) and (-), at the radio and audio amplifier have a DC bias voltage that is one half of the battery voltage. When using a DMM, each of the audio output channel circuits will measure approximately 6.5V 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. This voltage will vary depending on what type of audio is being listened to, talk or music, and type of music, as well as the volume setting of the system. Low volume and talk settings will measure around 1V AC and less, where constant music may measure 3V AC and slightly higher.

Conditions for Running the DTC

The radio is ON.

Conditions for Setting the DTC

Set by Radio

The radio sets a current status for this DTC when a short to ground, short to voltage or an open is detected on any of the speaker channel outputs from the radio.

Set by Bose Amplifier

The DTC will not set during normal amplifier operation. The vehicle must have the ignition OFF for several hours and the fault must be present during amplifier power-up.

DTC B1025 01, B1035 01, B1045 01, B1055 01, B1065 01, B1075 01, B1085 01, B1095 01

A short to voltage is detected on the specified (+) or (-) signal circuit

DTC B1025 02, B1035 02, B1045 02, B1055 02, B1065 02, B1075 02, B1085 02, B1095 02

A short to ground is detected on the specified (+) or (-) signal circuit

DTC B1025 04, B1035 04, B1045 04, B1055 04, B1065 04, B1075 04, B1085 04, B1095 04

An open is detected on the specified (+) or (-) signal circuit

Action Taken When the DTC Sets

No sound is present from one or more of the speakers.

Conditions for Clearing the DTC

Set by Radio

The fault condition becomes history if not present for 0.25 seconds.

Set by Bose Amplifier

The fault condition becomes history after the vehicle ignition has been OFF for several hours and then the ignition turns ON.

Diagnostic Aids

Speakers located in the front A-pillar are connected to the same channel as the speaker in the door. A DTC will only set after the amplifier only on up-level radios.

Reference Information

Schematic Reference

Radio/Navigation System Schematics

Connector End View Reference

Component Connector End Views

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 Verification

Radio ON, adjust the fade and balance controls on the radio to test all four channels individually. Each of the four channels should produce clear and even sound.

Circuit/System Testing

Important: This DTC can be set by either the radio or the amplifier. If the DTC was set by the radio, diagnose the appropriate audio output circuits to the speakers or the low level inputs to the amplifier (if equipped). If the DTC was set by the amplifier, diagnose audio output signals to the speakers from the amplifier. If equipped with rear seat audio (RSA) (U42), the RSA must be turned off to perform proper speaker testing.

Without Amplifier

  1. Ignition OFF, disconnect the harness connector at the appropriate speaker.
  2. Radio ON, test for 5.0-7.5 volts between the signal circuit terminal A and ground.
    3. ⇒If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio.
    ⇒If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.
  3. Test for 5.0-7.5 volts between the signal circuit terminal B and ground.
    4. ⇒If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio.
    ⇒If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.
  4. If all circuits test normal, replace the speaker.

DTC Set By The Radio UQA

  1. Ignition OFF, disconnect the X3 harness connector at the amplifier.
  2. Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below and ground.
    3. • Left front low level audio signal (+) - terminal 15
    • Left front low level audio signal (-) - terminal 7
    • Right front low level audio signal (+) - terminal 14
    • Right front low level audio signal (-) - terminal 6
    • Left rear low level audio signal (+) - terminal 13
    • Left rear low level audio signal (-) - terminal 5
    • Right rear low level audio signal (+) - terminal 12
    • Right rear low level audio signal (-) - terminal 4
    ⇒If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.
    ⇒If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio.
  3. If all circuits test normal, replace the amplifier.

DTC Set By Radio UQA with U42

  1. Ignition OFF, disconnect the X3 harness connector at the amplifier.
  2. Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below and ground.
    3. • Left front low level audio signal (+) - terminal 15
    • Left front low level audio signal (-) - terminal 7
    • Right front low level audio signal (+) - terminal 14
    • Right front low level audio signal (-) - terminal 6
    ⇒If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.
    ⇒If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio.
  3. Ignition OFF, reconnect the X3 harness connector at the amplifier.
  4. Disconnect the X2 harness connector at the rear seat audio (RSA) module.
  5. Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below and ground.
    6. • Left rear low level audio signal (+) - terminal 1
    • Left rear low level audio signal (-) - terminal 2
    • Right rear low level audio signal (+) - terminal 3
    • Right rear low level audio signal (-) - terminal 4
    ⇒If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the rear seat audio (RSA) module.
    ⇒If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the rear seat audio (RSA) module.
  6. Ignition OFF, reconnect the X2 harness connector at the rear seat audio (RSA) module.
  7. Disconnect the X3 harness connector at the amplifier.
  8. Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below and ground.
    9. • Left rear low level audio signal (+) - terminal 13
    • Left rear low level audio signal (-) - terminal 5
    • Right rear low level audio signal (+) - terminal 12
    • Right rear low level audio signal (-) - terminal 4
    ⇒If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the rear seat audio (RSA) module.
    ⇒If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the rear seat audio (RSA) module.
  9. If all circuits test normal, replace the amplifier.

DTC Set By Radio UQA with Y91 and U42 or UQS and U42

  1. Ignition OFF, disconnect the X3 and X4 harness connectors at the amplifier.
  2. Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below and ground.
    3. • Left front low level audio signal (+) - terminal 11 X3
    • Left front low level audio signal (-) - terminal 12 X3
    • Right front low level audio signal (+) - terminal 3 X3
    • Right front low level audio signal (-) - terminal 4 X3
    • Left rear low level audio signal (+) - terminal 11 X4
    • Left rear low level audio signal (-) - terminal 12 X4
    • Right rear low level audio signal (+) - terminal 3 X4
    • Right rear low level audio signal (-) - terminal 4 X4
    • Subwoofer low level audio signal (+) - terminal 5 X4
    • Subwoofer low level audio signal (-) - terminal 6 X4
    • Center Channel low level audio signal (+) - terminal 13 X4
    • Center Channel low level audio signal (-) - terminal 14 X4
    ⇒If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.
    ⇒If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio.
  3. If all circuits test normal, replace the amplifier.

DTC Set By Radio UQA with Y91 and U42 or UQS and U42

  1. Ignition OFF, disconnect the X3 and X4 harness connector at the amplifier.
  2. Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below and ground.
    3. • Left front low level audio signal (+) - terminal 11 X3
    • Left front low level audio signal (-) - terminal 12 X3
    • Right front low level audio signal (+) - terminal 3 X3
    • Right front low level audio signal (-) - terminal 4 X3
    • Subwoofer low level audio signal (+) - terminal 5 X4
    • Subwoofer low level audio signal (-) - terminal 6 X4
    • Center Channel low level audio signal (+) - terminal 13 X4
    • Center Channel low level audio signal (-) - terminal 14 X4
    ⇒If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.
    ⇒If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio.
  3. Ignition OFF, reconnect the X3 harness connector at the amplifier.
  4. Disconnect the X2 harness connector at the rear seat audio (RSA) module.
  5. Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below and ground.
    6. • Left rear low level audio signal (+) - terminal 1
    • Left rear low level audio signal (-) - terminal 2
    • Right rear low level audio signal (+) - terminal 3
    • Right rear low level audio signal (-) - terminal 4
    ⇒If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the rear seat audio (RSA) module.
    ⇒If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the rear seat audio (RSA) module.
  6. Ignition OFF, reconnect the X2 harness connector at the rear seat audio (RSA) module.
  7. Disconnect the X2 harness connector at the amplifier.
  8. Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below and ground.
    9. • Left rear low level audio signal (+) - terminal 15
    • Left rear low level audio signal (-) - terminal 14
    • Right rear low level audio signal (+) - terminal 16
    • Right rear low level audio signal (-) - terminal 8
    ⇒If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the rear seat audio (RSA) module.
    ⇒If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the rear seat audio (RSA) module.
  9. If all circuits test normal, replace the amplifier.

DTC Set by Audio Amplifier UQA

  1. Ignition OFF, disconnect the X1 and X2 connectors at the amplifier.
  2. Radio ON, test for less than 1 volt between the appropriate signal circuit terminal listed below and ground:
    3. • Left front speaker output (+) - terminal 4 X2
    • Left front speaker output (-) - terminal 3 X2
    • Right front speaker output (+) - terminal 2 X2
    • Right front low speaker output (-) - terminal 1 X2
    • Left rear speaker output (+) - terminal 8 X2
    • Left rear speaker output (-) - terminal 7 X2
    • Right rear speaker output (+) - terminal 6 X2
    • Right rear speaker output (-) - terminal 5 X2
    • Left or rear subwoofer speaker output (+) - terminal 7 X1
    • Left or rear subwoofer speaker output (-) - terminal 3 X1
    • Right subwoofer speaker output (+) - terminal 6 X1
    • Right subwoofer speaker output (-) - terminal 2 X1
    ⇒If greater than the specified range, test both circuits of the affected speaker for a short to voltage.
  3. Radio OFF, test for infinite resistance between the appropriate signal circuit terminal listed below and ground:
    4. • Left front speaker output (+) - terminal 4 X2
    • Left front speaker output (-) - terminal 3 X2
    • Right front speaker output (+) - terminal 2 X2
    • Right front low speaker output (-) - terminal 1 X2
    • Left rear speaker output (+) - terminal 8 X2
    • Left rear speaker output (-) - terminal 7 X2
    • Right rear speaker output (+) - terminal 6 X2
    • Right rear speaker output (-) - terminal 5 X2
    • Left or rear subwoofer speaker output (+) - terminal 7 X1
    • Left or rear subwoofer speaker output (-) - terminal 3 X1
    • Right subwoofer speaker output (+) - terminal 6 X1
    • Right subwoofer speaker output (-) - terminal 2 X1
    ⇒If less than the specified value, test both circuits of the affected speaker for a short to ground.
  4. If all circuits test normal, reconnect all harness connectors at the amplifier.
  5. Ignition ON, radio ON, disconnect the appropriate speaker.
  6. Test for 5.0-7.5 volts between the signal circuit terminals and ground.
    7. ⇒If less then the specified range test the circuit for an open/high resistance. If the circuit tests normal, replace the amplifier.
    ⇒If greater then the specified range test the circuit for a short to voltage. If the circuit tests normal, replace the amplifier.
  7. If the circuit tests normal, replace the appropriate speaker.

DTC Set by Audio Amplifier UQA with Y91 or UQS

  1. Ignition OFF, disconnect the X1 and X2 connectors at the amplifier.
  2. Radio ON, test for less than 1 volt between the appropriate signal circuit terminal listed below and ground:
    3. • Left front speaker output (+) - terminal 4 X2
    • Left front speaker output (-) - terminal 5 X2
    • Right front speaker output (+) - terminal 7 X2
    • Right front speaker output (-) - terminal 6 X2
    • Left rear speaker output (+) - terminal 15 X2
    • Left rear speaker output (-) - terminal 14 X2
    • Right rear speaker output (+) - terminal 16 X2
    • Right rear speaker output (-) - terminal 8 X2
    • Front center speaker output (+) - terminal 13 X2
    • Front center speaker output (-) - terminal 12 X2
    • Right rear midrange speaker output (+) - terminal 3 X2
    • Right rear midrange speaker output (-) - terminal 2 X2
    • Left rear midrange speaker output (+) - terminal 11 X2
    • Left rear midrange speaker output (-) - terminal 10 X2
    • Left or rear subwoofer speaker output (+) - terminal 1 X1
    • Left or rear subwoofer speaker output (-) - terminal 2 X1
    • Right subwoofer speaker output (+) - terminal 7 X1
    • Right subwoofer speaker output (-) - terminal 3 X1
    ⇒If greater than the specified range, test both circuits of the affected speaker for a short to voltage.
  3. Radio OFF, test for infinite resistance between the appropriate signal circuit terminal listed below and ground:
    4. • Left front speaker output (+) - terminal 4 X2
    • Left front speaker output (-) - terminal 5 X2
    • Right front speaker output (+) - terminal 7 X2
    • Right front speaker output (-) - terminal 6 X2
    • Left rear speaker output (+) - terminal 15 X2
    • Left rear speaker output (-) - terminal 14 X2
    • Right rear speaker output (+) - terminal 16 X2
    • Right rear speaker output (-) - terminal 8 X2
    • Front center speaker output (+) - terminal 13 X2
    • Front center speaker output (-) - terminal 12 X2
    • Right rear midrange speaker output (+) - terminal 3 X2
    • Right rear midrange speaker output (-) - terminal 2 X2
    • Left rear midrange speaker output (+) - terminal 11 X2
    • Left rear midrange speaker output (-) - terminal 10 X2
    • Left or rear subwoofer speaker output (+) - terminal 1 X1
    • Left or rear subwoofer speaker output (-) - terminal 2 X1
    • Right subwoofer speaker output (+) - terminal 7 X1
    • Right subwoofer speaker output (-) - terminal 3 X1
    ⇒If less than the specified value, test both circuits of the affected speaker for a short to ground.
  4. If all circuits test normal, reconnect all harness connectors at the amplifier.
  5. Radio ON, disconnect the appropriate speaker.
  6. Test for 5.0-7.5 volts between the signal circuit terminals and ground.
    7. ⇒If less then the specified range test the circuit for an open/high resistance. If the circuit tests normal, replace the amplifier.
    ⇒If greater then the specified range test the circuit for a short to voltage. If the circuit tests normal, replace the amplifier.
  7. If the circuit tests normal, replace the appropriate speaker.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Speaker Replacement Reference
    •  Control Module References for Amplifier and Radio replacement, setup, and programming