Speakers Inoperative - One or More. Cadillac DTS 2007

For 1990-2009 cars only

Makes 🢒 Cadillac 🢒 2007 🢒 DTS 🢒 Driver Information and Entertainment 🢒 Cellular, Entertainment, and Navigation 🢒 Speakers Inoperative - One or More

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 provides an overview of each diagnostic category.

Diagnostic Fault Information

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
Amplifier Battery Positive Voltage	1	1	--	--
Antenna 14V switched Supply Voltage	1	1	--	--
Left Front Low Level Audio Signal (+)/Left Front Speaker Signal (+)	B1025 02*	B1025 04*	B1025 01*	--
Left Front Low Level Audio Signal (-)/Left Front Speaker Signal (-)	B1025 02*	B1025 04*	B1025 01*	--
Right Front Low Level Audio Signal (+)/Right Front Speaker Signal (+)	B1035 02*	B1035 04*	B1035 01*	--
Right Front Low Level Audio Signal (-)/Right Front Speaker Signal (-)	B1035 02*	B1035 04*	B1035 01*	--
Left Rear Low Level Audio Signal (+)/Left Rear Speaker Signal (+)	B1045 02*	B1045 04*	B1045 01*	--
Left Rear Low Level Audio Signal (-)/Left Rear Speaker Signal (-)	B1045 02*	B1045 04*	B1045 01*	--
Right Rear Low Level Audio Signal (+)/Right Rear Speaker Signal (+)	B1055 02*	B1055 04*	B1055 01*	--
Right Rear Low Level Audio Signal (-)/Right Rear Speaker Signal (-)	B1055 02*	B1055 04*	B1055 01*	--
Front Center Speaker Signal (+)	B1065 02*	B1065 04*	B1065 01*	--
Front Center Speaker Signal (-)	B1065 02*	B1065 04*	B1065 01*	--
Subwoofer Audio Signal (+)	B1075 02*	B1075 04*	B1075 01*	--
Subwoofer Audio Signal (-)	B1075 02*	B1075 04*	B1075 01*	--
Amplifier Ground	--	1	--	--
1. Amplifier inoperative/no sound from speakers * Speaker output DTCs available when equipped with amplifier UQA only

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

Amplifier UQA

The radio provides left and right audio signals to the amplifier. The amplifier is supplied battery voltage from a dedicated fuse in the rear fuse block. The amplifier communicates with the vehicle via serial data, which controls the power state of the amplifier and allows the amplifier to set DTCs. Balance/fade and muting functions are all performed by the amplifier based on serial data messages.

Amplifier UQ3

The radio provides four channels of audio signals to the amplifier- left front, left rear, right front and right rear. The amplifier is supplied battery voltage from a dedicated fuse in the rear fuse block. The amplifier power state is controlled by a remote enable signal via the antenna 14V switched supply circuit, which also provides power to the antenna module. Amplifier muting functions are controlled by a dedicated pulse width modulated signal from the radio via the amp control circuit. The amplifier provides eight audio output channels to the speakers. This amplifier does not communicate on the serial data bus and cannot set DTCs.

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.

•	When equipped with an amplifier, it is possible for some individual circuit faults to affect more than one speakers operation. Perform diagnostic tests in the sequence listed to avoid misdiagnosis.

Reference Information

Schematic Reference

Radio/Navigation System Schematics

Connector End View Reference

Entertainment/Communication Connector End Views

Electrical Information Reference

•	Circuit Testing

•	Connector Repairs

•	Testing for Intermittent Conditions and Poor Connections

•	Wiring Repairs

Scan Tool Reference

Scan Tool Data List

Circuit/System Verification

Radio ON, verify clear audio is heard from each audio speaker.

⇒	If audio is inoperative from all speakers, refer to Amplifier Circuit Malfunction.

⇒	If audio is inoperative from one or more, but not all, speakers or the audio emitted from the speakers is not clear, refer to Speaker Circuit Malfunction

Circuit/System Testing

Amplifier Circuit Malfunction with UQ3

Ignition OFF, disconnect the C1 harness connector at the amplifier.
Test for less than 10 ohms of resistance between the ground circuit terminal 2 and ground.

⇒	If greater than the specified range, test the ground circuit for an open/high resistance.

Ignition ON, verify a test lamp illuminates between the B+ circuit terminal 1 and ground.

⇒	If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the circuit fuse is open, replace the amplifier.

Disconnect the C3 harness connector at the amplifier.
Radio ON, test for 0.5-1.0 volts between the signal circuit terminal 5 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.

Verify a test lamp illuminates between the signal circuit terminal 6 and ground.

⇒	If the test lamp does not illuminate, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.

If all circuits test normal, replace the amplifier.

Speaker Circuit Malfunction with UQ3

Ignition OFF, disconnect the C3 harness connector at the amplifier.
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 2

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

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

•	Left rear low level audio signal (+) -terminal 4

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

•	Right rear low level audio signal (+) -terminal 11

•	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 radio.

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

Ignition OFF, disconnect the C1 and C2 harness connectors at the amplifier.
Ignition ON, test for less than 1 volt between each of the signal circuit terminals listed below and ground.

•	Front center speaker output (+) -terminal 3 C1

•	Front center speaker output (-)-terminal 4 C1

•	Subwoofer speaker output (+) -terminal 8 C1

•	Subwoofer speaker output (-)-terminal 7 C1

•	Left front tweeter speaker output (+)- terminal 1 C2

•	Left front tweeter speaker output (-)-terminal 2 C2

•	Right front tweeter speaker output (+)- terminal 3 C2

•	Right front tweeter speaker output (-) -terminal 4 C2

•	Left front speaker output (+)- terminal 15 C2

•	Left front speaker output (-)-terminal 16 C2

•	Right front speaker output (+)- terminal 13 C2

•	Right front speaker output (-) -terminal 14 C2

•	Left rear speaker output (+) -terminal 6 C2

•	Left rear speaker output (-) -terminal 5 C2

•	Right rear speaker output (+)- terminal 8 C2

•	Right rear speaker output (-)- terminal 7 C2

⇒	If greater than the specified range, test both signal circuits of the affected speaker for a short to voltage.

Ignition OFF, test for infinite resistance between each of the signal circuit terminals listed below and ground.

•	Front center speaker output (+) -terminal 3 C1

•	Front center speaker output (-)-terminal 4 C1

•	Subwoofer speaker output (+) -terminal 8 C1

•	Subwoofer speaker output (-)-terminal 7 C1

•	Left front tweeter speaker output (+)- terminal 1 C2

•	Left front tweeter speaker output (-)-terminal 2 C2

•	Right front tweeter speaker output (+)- terminal 3 C2

•	Right front tweeter speaker output (-) -terminal 4 C2

•	Left front speaker output (+)- terminal 15 C2

•	Left front speaker output (-)-terminal 16 C2

•	Right front speaker output (+)- terminal 13 C2

•	Right front speaker output (-) -terminal 14 C2

•	Left rear speaker output (+) -terminal 6 C2

•	Left rear speaker output (-) -terminal 5 C2

•	Right rear speaker output (+)- terminal 8 C2

•	Right rear speaker output (-)- terminal 7 C2

⇒	If less than the specified value, test both signal circuits of the affected speaker for a short to ground.

Reconnect all harness connectors at the amplifier. Disconnect the harness connector at the appropriate speaker.
Radio ON, test for 5.0-7.5 volts between each of the appropriate signal circuit terminals listed below and ground.

•	Front tweeter speakers - terminals A and B

•	Center IP speaker- terminals A and B

•	Door speakers - terminals A and B

•	Subwoofer speaker - terminals A and B

⇒	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 audio amplifier.

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

If all circuits test normal, replace the inoperative speaker.

Speaker Circuit Malfunction with UQA

Ignition OFF, disconnect the C3 harness connector at the audio amplifier.
Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below and ground.

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

•	Left low level audio signal (-) -terminal 12

•	Right low level audio signal (+) -terminal 3

•	Right low level audio signal (-) -terminal 4

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

Ignition OFF, disconnect the C1 and C2 harness connectors at the amplifier.
Ignition ON, test for less than 1 volt between each of the signal circuit terminals listed below and ground.

•	Subwoofer speaker output (+)- terminal 1 C1

•	Subwoofer speaker output (-) -terminal 2 C1

•	Left front speaker output (+)- terminal 4 C2

•	Left front speaker output (-)-terminal 5 C2

•	Right front speaker output (+)- terminal 7 C2

•	Right front speaker output (-) -terminal 6 C2

•	Left rear speaker output (+) -terminal 15 C2

•	Left rear speaker output (-) -terminal 14 C2

•	Right rear speaker output (+)- terminal 16 C2

•	Right rear speaker output (-)- terminal 8 C2

•	Front center speaker output (+) -terminal 13 C2

•	Front center speaker output (-)-terminal 12 C2

⇒	If greater than the specified range, test both signal circuits of the affected speaker for a short to voltage.

Ignition OFF, test for infinite resistance between each of the signal circuit terminals listed below and ground.

•	Subwoofer speaker output (+)- terminal 1 C1

•	Subwoofer speaker output (-) -terminal 2 C1

•	Left front speaker output (+)- terminal 4 C2

•	Left front speaker output (-)-terminal 5 C2

•	Right front speaker output (+)- terminal 7 C2

•	Right front speaker output (-) -terminal 6 C2

•	Left rear speaker output (+) -terminal 15 C2

•	Left rear speaker output (-) -terminal 14 C2

•	Right rear speaker output (+)- terminal 16 C2

•	Right rear speaker output (-)- terminal 8 C2

•	Front center speaker output (+) -terminal 13 C2

•	Front center speaker output (-)-terminal 12 C2

⇒	If less than the specified value, test both signal circuits of the affected speaker for a short to ground.

Reconnect all harness connectors at the amplifier. Disconnect the harness connector at the appropriate speaker.
Radio ON, test for 5.0-7.5 volts between each of the appropriate signal circuit terminals listed below and ground.

•	Front tweeter speakers - terminals A and B

•	Center IP speaker- terminals A and B

•	Door speakers - terminals A and B

•	Subwoofer speaker - terminals A and B

⇒	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 audio amplifier.

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

If all circuits test normal, replace the inoperative speaker.

Repair Instructions

Perform the Diagnostic Repair Verification Diagnostic Repair Verification Diagnostic Repair Verification after completing the diagnostic procedure.

•	Speaker Replacement Reference

•	Control Module References for radio or amplifier replacement, setup, and programming