Diagnostic Instructions

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

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

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

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

Diagnostic Fault Information

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
Left Front Speaker Output (+)/Left Front Low Level Audio Signal (+)	B1025 02, *	1	B1025 01, *	--
Left Front Speaker Output (-)/Left Front Low Level Audio Signal (-)	B1025 02, *	1	B1025 01, *	--
Right Front Speaker Output (+)/Right Front Low Level Audio Signal (+)	B1035 02, *	1	B1035 01, *	--
Right Front Speaker Output (-)/Right Front Low Level Audio Signal (-)	B1035 02, *	1	B1035 01, *	--
Left Rear Speaker Output (+)/Left Rear Low Level Audio Signal (+)	B1045 02, *	1	B1045 01, *	--
Left Rear Speaker Output (-)/Left Rear Low Level Audio Signal (-)	B1045 02, *	1	B1045 01, *	--
Right Rear Speaker Output (+)/Right Rear Low Level Audio Signal (+)	B1055 02, *	1	B1055 01, *	--
Right Rear Speaker Output (-)/Right Rear Low Level Audio Signal (-)	B1055 02, *	1	B1055 01, *	--
1. No or reduced audio * 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

Conditions for Setting the DTC

The DTC will set when the radio detects a short to voltage or short to ground in any of the low level audio signal circuits (+) and (-).

Action Taken When the DTC Sets

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

Conditions for Clearing the DTC

Reference Information

Schematic Reference

Radio/Navigation System Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Radio/Audio System Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

Circuit/System 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.

⇒	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. Test for 5.0-7.5 volts between the signal circuit terminal B and ground.

⇒	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.

4. If all circuits test normal, replace the speaker.

With Amplifier

1. Ignition OFF, disconnect the harness connector at the rear seat audio (RSA) controller.
2. Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below and ground.

•	Left rear low level audio signal (+) terminal A4

•	Left rear low level audio signal (-) terminal A3

•	Right rear low level audio signal (+) terminal A2

•	Right rear low level audio signal (-) terminal A1

⇒	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 harness connector at the rear seat audio (RSA) controller.
4. Disconnect the X3 harness connector at the audio amplifier.
5. Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below and ground.

•	Left rear low level audio signal (+) terminal 3

•	Left rear low level audio signal (-) terminal 11

•	Right rear low level audio signal (+) terminal 4

•	Right rear low level audio signal (-) terminal 12

⇒	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) controller.

⇒	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) controller.

6. Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below and ground.

•	Left front low level audio signal (+) terminal 1

•	Left front low level audio signal (-) terminal 9

•	Right front low level audio signal (+) terminal 2

•	Right front low level audio signal (-) terminal 10

⇒	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.

7. If all circuits test normal, replace the audio amplifier.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.