Pinpoint Test B: Poor Quality/Distorted/No Sound From One Or More Speakers (Not All Speakers) - Premium Sound
Information and Entertainment System
Pinpoint Tests
Pinpoint Test B: Poor Quality/Distorted/No Sound From One Or More Speakers (Not All Speakers) - Premium Sound
Refer to Wiring Diagram Set 130, Audio System/Navigation for schematic and connector information. Diagrams By Number
Normal Operation
The Audio Control Module (ACM) directs audio signals to the audio amplifier and subwoofer amplifier in the form of an AC voltage. The amplifiers boost the audio signals and send them to the speakers. The ACM provides internal circuit protection for shorts to ground or shorts to voltage.
If the vehicle is equipped with the family entertainment system, the rear channel audio signals from the ACM route to the Rear Entertainment Module (RETM), then to the amp or speakers. In dual-play mode, the RETM mutes the rear speaker output. Make sure the audio system is in single-play mode before diagnosing a rear speaker concern.
A short to ground or short to voltage in the circuitry to one of the speakers may cause multiple speakers to lose sound due to the built-in overload protection feature of the ACM. In this case, a speaker fault DTC sets, and this pinpoint test should be followed to isolate the damaged circuit.
The speaker walk test can be used to isolate a concern with a particular speaker. This can reduce the diagnostic steps necessary to isolate the concern. To carry out the speaker walk test, refer to Audio Control Module (ACM) Self-Diagnostic Mode Audio Control Module (ACM) Self-Diagnostic Mode.
To enable the amplifiers, the ACM sends voltage through individual enable/clip circuits. The circuits act as both an output (to enable the amplifier) and an input (to detect an overload condition). The voltage sent by the ACM passes through a variable resistor in each amplifier, then to ground. As the amplifier reaches maximum output, the resistance in the variable resistor decreases. This decreases the voltage drop, resulting in the ACM detecting a higher voltage on the enable/clip circuit. When the voltage reaches the clip threshold, the ACM clips the audio output signal to the amplifier (heard as distortion), in order to prevent damage to the amplifier and speakers.
The enable/clip status is based on the following voltages, as detected by the ACM:
- Less than 0.4 volt: amplifier disabled
- Between 3.8 and 6.7 volts (nominal): amplifier enabled
- Greater than 8.5 volts: amplifier clipped
An open in the enable/clip circuit causes the speakers powered by that particular amplifier to produce no sound because the enable signal does not reach the audio amplifier. A short to ground or short to voltage can cause severe distortion to be heard in the speakers.
- DTC B1A05:01 (Speaker #5: General Electrical Failure) - sets when a fault is detected in the audio circuits to the subwoofer amplifier. This DTC can be continuous or on-demand.
- DTC B1A06:01 (Speaker #6: General Electrical Failure) - sets when a fault is detected in the instrument panel speaker audio circuits to the audio amplifier. This DTC can be continuous or on-demand.
This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- Speaker
- Audio amplifier
- Speaker enclosure
- ACM
- RETM (if equipped)
PINPOINT TEST B: POOR QUALITY/DISTORTED/NO SOUND FROM ONE OR MORE SPEAKERS (NOT ALL SPEAKERS) - PREMIUM SOUND
NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
NOTE: Failure to disconnect the battery when instructed will result in false resistance readings. Refer to Battery.
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B1 DETERMINE THE INOPERATIVE SPEAKER(S)
- Carry out the speaker walk test. Refer to Audio Control Module (ACM) Self-Diagnostic Mode Audio Control Module (ACM) Self-Diagnostic Mode.
- Is the concern only with the subwoofer speaker?
Yes
GO to B2.
No
If the concern is only with an A-pillar speaker, GO to B10.
For all other concerns, GO to B13.
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B2 CHECK THE SUBWOOFER AMPLIFIER VOLTAGE SUPPLY
- Ignition OFF.
- Disconnect: Subwoofer Amplifier C466a.
- Measure the voltage between the subwoofer amplifier C466a-5, circuit SBP19 (BU/RD), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to B3.
No
VERIFY the Smart Junction Box (SJB) fuse 19 (25A) is OK. If OK, REPAIR the circuit. CLEAR any DTCs present. TEST the system for normal operation. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short. Diagrams By Number
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B3 CHECK THE SUBWOOFER AMPLIFIER GROUND FOR CONTINUITY
- Ignition OFF.
- Disconnect: Negative Battery Cable.
- Measure the resistance between the subwoofer amplifier C466a-2, circuit GD148 (BK/YE), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
GO to B4.
No
REPAIR the circuit. CLEAR any DTCs present. TEST the system for normal operation.
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B4 CHECK THE SUBWOOFER AMPLIFIER ENABLE CIRCUIT FOR CORRECT VOLTAGE
- Connect: Negative Battery Cable.
- Operate the audio system in radio tuner (AM/FM) mode.
- Measure the voltage between the subwoofer amplifier C466a-1, circuit SME23 (VT/RD), harness side and ground.
- Is the voltage between 3.8 and 6.7 volts?
Yes
GO to B5.
No
GO to B7.
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B5 CHECK THE SUBWOOFER AMPLIFIER ENABLE CIRCUIT FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: ACM C240d.
- Ignition ON.
- Measure the voltage between the subwoofer amplifier C466a-1, circuit SME23 (VT/RD), harness side and ground.
- Is any voltage present?
Yes
REPAIR the circuit. TEST the system for normal operation.
No
GO to B6.
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B6 CHECK THE SUBWOOFER AMPLIFIER ENABLE CIRCUIT FOR AN OPEN OR SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between the subwoofer amplifier C466a-1, circuit SME23 (VT/RD), harness side and the ACM C240d-4, circuit SME23 (VT/RD), harness side; and between the subwoofer amplifier C466a-1, circuit SME23 (VT/RD), harness side and ground.
- Is the resistance less than 5 ohms between the subwoofer amplifier and the ACM, and greater than 10,000 ohms between the subwoofer amplifier and ground?
Yes
GO to B27.
No
REPAIR the circuit. TEST the system for normal operation.
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B7 CHECK THE AUDIO SIGNAL TO THE SUBWOOFER AMPLIFIER
- Operate the audio system in radio tuner (AM/FM) mode.
- Measure the AC voltage between the subwoofer amplifier C466a-7, circuit VME22 (VT/GN), harness side and the subwoofer amplifier C466a-8, circuit RME22 (GN/WH), harness side.
- Is a fluctuating AC voltage present?
Yes
INSTALL a new speaker enclosure. REFER to Speaker Enclosure Speaker Enclosure CLEAR any DTCs present. TEST the system for normal operation.
No
GO to B8.
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B8 CHECK THE AUDIO CIRCUITS TO THE SUBWOOFER AMPLIFIER FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: ACM C240d.
- Ignition ON.
- Measure the voltage between the subwoofer amplifier C466a-7, circuit VME22 (VT/GN), harness side and ground; and between the subwoofer amplifier C466a-8, circuit RME22 (GN/WH), harness side and ground.
- Is any voltage present?
Yes
REPAIR the circuit in question. CLEAR any DTCs present. TEST the system for normal operation.
No
GO to B9.
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B9 CHECK THE AUDIO CIRCUITS TO THE SUBWOOFER AMPLIFIER FOR AN OPEN OR SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between the subwoofer amplifier, harness side and the ACM, harness side; and between the subwoofer amplifier, harness side and ground as follows:
- Is the resistance less than 5 ohms between the subwoofer amplifier and the ACM, and greater than 10,000 ohms between the subwoofer amplifier and ground?
Yes
GO to B27.
No
REPAIR the circuit in question. CLEAR any DTCs present. TEST the system for normal operation.
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B10 CHECK FOR AN AUDIO SIGNAL TO THE SUSPECT A-PILLAR SPEAKER
- Ignition OFF.
- Disconnect: Suspect A-Pillar Speaker.
- Operate the audio system in radio tuner (AM/FM) mode.
- Measure the AC voltage between the suspect A-pillar speaker pin 1 and pin 2, harness side as follows:
- Is a fluctuating AC voltage present?
Yes
INSTALL a new speaker for the suspect speaker. REFER to Speaker - A-Pillar Speaker - A-Pillar. TEST the system for normal operation.
No
GO to B11.
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B11 CHECK THE CIRCUITS TO THE SUSPECT A-PILLAR SPEAKER FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: LF Door Speaker C523b (LH Speaker Concern) or RF Door Speaker C652b (RH Speaker Concern).
- Ignition ON.
- Measure the voltage between the suspect A-pillar speaker, harness side and ground as follows:
- Is any voltage present?
Yes
REPAIR the circuit in question. TEST the system for normal operation.
No
GO to B12.
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B12 CHECK THE CIRCUITS TO THE SUSPECT A-PILLAR SPEAKER FOR AN OPEN OR SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between the suspect A-pillar speaker, harness side and the door speaker, harness side; and between the suspect A-pillar speaker, harness side and ground as follows:
- Is the resistance less than 5 ohms between the suspect A-pillar speaker and the door speaker, and greater than 10,000 ohms between the suspect A-pillar speaker and ground?
Yes
INSTALL a new door speaker. REFER to Speaker - Door Speaker - Door. TEST the system for normal operation.
No
REPAIR the circuit in question. TEST the system for normal operation.
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B13 CHECK THE AUDIO SIGNALS TO THE SUSPECT SPEAKER
- Ignition OFF.
- Disconnect: Suspect Speaker.
- Operate the audio system in radio tuner (AM/FM), single-play mode.
- Measure the AC voltage between the suspect speaker pins, harness side as follows:
- Is a fluctuating AC voltage present?
Yes
INSTALL a new speaker for the suspect speaker. REFER to Speaker - Door Speaker - Door or Speaker - Instrument Panel Speaker - Instrument Panel. TEST the system for normal operation.
No
If the vehicle is equipped with the family entertainment system and the concern is with a rear speaker, GO to B14.
Otherwise, GO to B17.
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B14 CHECK THE AUDIO SIGNALS TO THE RETM
- Ignition OFF.
- Disconnect: RETM C2949b.
- Operate the audio system in radio tuner (AM/FM), single-play mode.
- Measure the AC voltage between the RETM C2949b-8, circuit VME59 (YE/OG), harness side and the RETM C2949b-21, circuit RME59 (WH/GN), harness side.
- Measure the AC voltage between the RETM C2949b-22, circuit VME58 (YE/VT), harness side and the RETM C2949b-9, circuit RME58 (BN/BU), harness side.
- Is a fluctuating AC voltage present?
Yes
GO to B17.
No
GO to B15.
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B15 CHECK THE AUDIO CIRCUITS TO THE RETM FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: ACM C240a.
- Ignition ON.
- Measure the voltage between the RETM, harness side and ground as follows:
- Is any voltage present?
Yes
REPAIR the circuit in question. TEST the system for normal operation.
No
GO to B16.
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B16 CHECK THE AUDIO CIRCUITS TO THE RETM FOR AN OPEN OR SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between the ACM, harness side and the RETM, harness side; and between the ACM, harness side and ground as follows:
- Are the resistances less than 5 ohms between the ACM and the RETM, and greater than 10,000 ohms between the ACM and ground?
Yes
GO to B27.
No
REPAIR the circuit in question. TEST the system for normal operation.
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B17 CHECK THE AUDIO AMPLIFIER VOLTAGE SUPPLY
- Ignition OFF.
- Disconnect: Audio Amplifier C4208b.
- Measure the voltage between the audio amplifier C4208b-12, circuit SBP18 (YE/RD), harness side and the audio amplifier C4208b-24, circuit SBP18 (YE/RD), harness side.
- Are the voltages greater than 10 volts?
Yes
GO to B18.
No
VERIFY the SJB fuse 18 (20A) is OK. If OK, REPAIR the circuit in question. TEST the system for normal operation. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short. Diagrams By Number
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B18 CHECK THE AUDIO AMPLIFIER GROUND CIRCUITS FOR CONTINUITY
- Ignition OFF.
- Disconnect: Negative Battery Cable.
- Measure the resistance between the audio amplifier C4208b-21, circuit GD148 (BK/YE), harness side; and between the audio amplifier C4208b-22, circuit GD148 (BK/YE), harness side.
- Are the resistances less than 5 ohms?
Yes
GO to B19.
No
REPAIR the circuit in question. TEST the system for normal operation.
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B19 CHECK THE AUDIO AMPLIFIER ENABLE CIRCUIT FOR CORRECT VOLTAGE
- Ignition OFF.
- Connect: Audio Amplifier C4208b.
- Disconnect: Audio Amplifier C4208a.
- Operate the audio system in radio tuner (AM/FM) mode.
- Measure the voltage between the audio amplifier C4208a-11, circuit CME31 (BU/GN), harness side and ground.
- Is the voltage between 3.8 and 6.7 volts?
Yes
GO to B22.
No
GO to B20.
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B20 CHECK THE AUDIO AMPLIFIER ENABLE CIRCUIT FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: ACM C240d.
- Ignition ON.
- Measure the voltage between the audio amplifier C4208a-11, circuit CME31 (BU/GN), harness side and ground.
- Is any voltage present?
Yes
REPAIR the circuit in question. TEST the system for normal operation.
No
GO to B21.
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B21 CHECK THE AUDIO AMPLIFIER ENABLE CIRCUIT FOR AN OPEN OR SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between the audio amplifier C4208a-11, circuit CME31 (BU/GN), harness side and the ACM C240a-7, circuit CME31 (BU/GN), harness side; and between the audio amplifier C4208a-11, circuit CME31 (BU/GN), harness side and ground.
- Is the resistance less than 5 ohms between audio amplifier and the ACM, and greater than 10,000 ohms between audio amplifier and ground?
Yes
GO to B27.
No
REPAIR the circuit. TEST the system for normal operation.
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B22 CHECK THE AUDIO SIGNALS TO THE AUDIO AMPLIFIER
- Operate the audio system in radio tuner (AM/FM) mode.
- Measure the AC voltage between the audio amplifier pins, harness side as follows:
- Is a fluctuating AC voltage present?
Yes
GO to B25.
No
GO to B23.
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B23 CHECK THE AUDIO CIRCUITS TO THE AUDIO AMPLIFIER FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: ACM C240a (Vehicles Without the Family Entertainment System).
- Disconnect: ACM C240d (Instrument Panel Speaker Concern).
- Disconnect: RETM C2949b (Vehicles With the Family Entertainment System).
- Ignition ON.
- Measure the voltage between the audio amplifier, harness side and ground as follows:
- Is any voltage present?
Yes
REPAIR the circuit in question. CLEAR any DTCs present. TEST the system for normal operation.
No
GO to B24.
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B24 CHECK THE CIRCUITS TO THE AUDIO AMPLIFIER FOR AN OPEN OR SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between the ACM (or RETM, if equipped with the family entertainment system), harness side and the audio amplifier, harness side; and between the ACM (or RETM, if equipped with the family entertainment system), harness side and ground as follows:
- Is the resistance less than 5 ohms between the ACM (or RETM) and the audio amplifier, and greater than 10,000 ohms between the ACM (or RETM) and ground?
Yes
If the vehicle is equipped with the family entertainment system, GO to B28.
Otherwise, GO to B27.
No
REPAIR the circuit in question. CLEAR any DTCs present. TEST the system for normal operation.
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B25 CHECK THE AUDIO CIRCUITS TO THE SUSPECT SPEAKER FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: Suspect Speaker.
- Disconnect: Audio Amplifier C4208b.
- Ignition ON.
- Measure the voltage between the suspect speaker, harness side and ground as follows:
- Is any voltage present?
Yes
REPAIR the circuit in question. TEST the system for normal operation.
No
GO to B26.
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B26 CHECK THE AUDIO CIRCUITS TO THE SUSPECT SPEAKER FOR AN OPEN OR SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between the audio amplifier, harness side and the suspect speaker, harness side; and between the audio amplifier, harness side and ground as follows:
- Are the resistances less than 5 ohms between the audio amplifier and the suspect speaker, and greater than 10,000 ohms between the audio amplifier and ground?
Yes
INSTALL a new audio amplifier. REFER to Audio Amplifier Service and Repair. TEST the system for normal operation.
No
REPAIR the circuit in question. TEST the system for normal operation.
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B27 CHECK FOR CORRECT ACM OPERATION
- Ignition OFF.
- Connect: All Disconnected Connectors.
- Disconnect all the ACM connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect the ACM connectors and make sure they seat correctly.
- Operate the system and determine if the concern is still present.
- Is the concern still present?
Yes
INSTALL a new ACM. REFER to Audio Control Module (ACM) Audio Control Module (ACM). TEST the system for normal operation.
No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR any DTCs present. TEST the system for normal operation.
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B28 CHECK FOR CORRECT RETM OPERATION
- Ignition OFF.
- Connect: All Disconnected Connectors.
- Disconnect the RETM connector.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect the RETM connector and make sure it seats correctly.
- Operate the system and determine if the concern is still present.
- Is the concern still present?
Yes
INSTALL a new RETM. REFER to Rear Entertainment Module (RETM) Rear Entertainment Module (RETM). TEST the system for normal operation.
No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR any DTCs present. TEST the system for normal operation.
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