Service Information

Volt

DTC B1025, B1035, B1045, or B1055

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 B1025 01: Left Front Audio Output Circuit Short to Battery

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

DTC B1025 04: Left Front Audio Output Circuit Open

DTC B1035 01: Front Audio Output Circuit Short to Battery

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

DTC B1035 04: Right Front Audio Output Circuit Open

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

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

DTC B1045 04: Left Rear Audio Output Circuit Open

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

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

DTC B1055 04: Right Rear Audio Output Circuit Open

Diagnostic Fault Information

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
Left Front Audio Signal Circuit	B1025 02*	B1025 04**	B1025 01*	--
Right Front Audio Signal Circuit	B1035 02*	B1035 04**	B1035 01*	--
Left Rear Audio Signal Circuit	B1045 02*	B1045 04**	B1045 01*	--
Right Rear Audio Signal Circuit	B1055 02*	B1055 04**	B1055 01*	--
* Noticeable audio distortion possible. ** No or reduced sound from speaker.

Circuit/System Description

Each of the audio output channel circuits (+) and (-), at the radio and audio amplifier has 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 centred 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.

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. If the speaker or surrounding interior trim is found to be loose or improperly secured, correctly secure the item.

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.

Reference Information

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 Testing

Vehicle OFF, disconnect the harness connector at the appropriate P19 speaker.
Radio ON, test for 5.0-7.5 V between the signal circuit terminal 1 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 A11 radio.

⇒	If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the A11 radio.

Test for 5.0-7.5 V between the signal circuit terminal 2 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 A11 radio.

⇒	If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the A11 radio.

If all circuits test normal, replace the appropriate P19 speaker.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

•	Speaker Replacement Reference

•	Control Module References for radio replacement, setup, and programming.