Pinpoint Test C: Poor Quality/Distorted/No Sound From One Or More Speakers (Not All Speakers) - THX(R)
Information and Entertainment System
Pinpoint Test C: Poor Quality/Distorted/No Sound From One Or More Speakers (Not All Speakers) - THX(R)
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 Digital Signal Processing (DSP) module in the form of an AC voltage. The audio DSP module boosts the audio signals and sends them to the speakers. The audio DSP module provides internal circuit protection for shorts to ground or voltage.
A short to ground or voltage in the circuitry to one of the speakers can cause multiple speakers on the same channel, or even all speakers to lose sound due to the built-in overload protection feature of the audio DSP module. In this case, a speaker fault DTC sets, and this pinpoint test should be followed to isolate the damaged circuit.
The ACM sends the audio signals to the audio DSP module in the following banks:
A concern in the circuits from the ACM to the audio DSP module may not set an ACM DTC.
It is also important to note that if the navigation voice guidance setting is set too low, it may appear that the front speakers intermittently produce no sound. Make sure the voice guidance setting is not set high enough to hear the voice guidance commands before addressing a concern with the front speakers.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Speaker
- Subwoofer speaker
- Audio DSP module
- ACM
PINPOINT TEST C: POOR QUALITY/DISTORTED/NO SOUND FROM ONE OR MORE SPEAKERS (NOT ALL SPEAKERS) - THX(R)
NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
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C1 DETERMINE THE INOPERATIVE SPEAKER(S)
- Enter the following diagnostic mode on the scan tool: Speaker Walkaround Test.
- Follow the scan tool on-screen instructions to carry-out the speaker walkaround test.
- Is the concern only with an A-pillar speaker or the LH/RH instrument panel speaker?
Yes
GO to C2.
No
If the concern is with a rear door tweeter speaker, GO to C8.
For all other speakers, GO to C11.
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C2 CHECK FOR VOLTAGE TO THE SUSPECT A-PILLAR OR INSTRUMENT PANEL SPEAKER
- Ignition OFF.
- Disconnect: Suspect Speaker.
- Operate the audio system in radio tuner (AM/FM) mode.
- Measure the AC voltage between the suspect 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 or Speaker - Instrument Panel Speaker - Instrument Panel. CLEAR any DTCs present. TEST the system for normal operation.
No
GO to C3.
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C3 CHECK FOR VOLTAGE TO THE CROSSOVER
- Ignition OFF.
- Disconnect: LH Crossover C590 (LH Speaker Concern) or RH Crossover C690 (RH Speaker Concern).
- Operate the audio system in radio tuner (AM/FM) mode.
- Measure the AC voltage between the LH crossover C590-1, circuit VME15 (GN/BU), harness side and the LH crossover C590-4, circuit RME15 (GY/BU), harness side; or between the RH crossover C690-1, circuit VME16 (VT/GY), harness side and the RH crossover C690-4, circuit RME16 (YE/GY), harness side.
- Is a fluctuating AC voltage present?
Yes
GO to C6.
No
GO to C4.
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C4 CHECK THE CIRCUITS TO THE CROSSOVER FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: Audio DSP Module C4326b.
- Ignition ON.
- Measure the voltage between the suspect crossover, 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 C5.
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C5 CHECK THE CIRCUITS TO THE CROSSOVER FOR AN OPEN OR SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between the suspect crossover, harness side and the audio DSP module, harness side; and between the suspect crossover, harness side and ground as follows:
- Is the resistance less than 5 ohms between the suspect crossover and the audio DSP module, and greater than 10,000 ohms between the suspect crossover and ground?
Yes
GO to C17.
No
REPAIR the circuit in question. CLEAR any DTCs present. TEST the system for normal operation.
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C6 CHECK THE CIRCUITS FROM THE CROSSOVER FOR A SHORT TO VOLTAGE
- Ignition ON.
- Measure the voltage between the suspect crossover, 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 C7.
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C7 CHECK THE CIRCUITS FROM THE CROSSOVER FOR AN OPEN OR SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between the suspect crossover, harness side and the speaker, harness side; and between the suspect crossover, harness side and ground as follows:
- Is the resistance less than 5 ohms between the suspect crossover and the suspect speaker, and greater than 10,000 ohms between the suspect crossover and ground?
Yes
INSTALL a new crossover for the suspect crossover. REFER to Speaker - Door Speaker - Door. CLEAR any DTCs present. TEST the system for normal operation.
No
REPAIR the circuit in question. CLEAR any DTCs present. TEST the system for normal operation.
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C8 CHECK FOR VOLTAGE TO THE SUSPECT REAR DOOR TWEETER SPEAKER
- Ignition OFF.
- Disconnect: Suspect Speaker.
- Operate the audio system in radio tuner (AM/FM) mode.
- Measure the AC voltage between the LH rear door tweeter speaker C730-1, circuit VME39 (GN/BN), harness side and the LH rear door tweeter speaker C730-2, circuit RME39 (GY/BN), harness side; or between the RH rear door tweeter speaker C830-1, circuit VME40 (BU/WH), harness side and the RH rear door tweeter speaker C830-2, circuit RME40 (VT/WH), harness side.
- Is a fluctuating AC voltage present?
Yes
INSTALL a new speaker for the suspect speaker. REFER to Speaker - Door Speaker - Door. CLEAR any DTCs present. TEST the system for normal operation.
No
GO to C9.
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C9 CHECK THE CIRCUITS TO THE REAR DOOR TWEETER FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: LH Rear Door Speaker C712b (LH Rear Door Tweeter Concern) or RH Rear Door Speaker C813b (RH Rear Door Tweeter Concern).
- 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. CLEAR any DTCs present. TEST the system for normal operation.
No
GO to C10.
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C10 CHECK THE CIRCUITS TO THE REAR DOOR TWEETER FOR AN OPEN OR SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between the door speaker, harness side and the suspect door tweeter speaker, harness side; and between the door speaker, harness side and ground as follows:
- Is the resistance less than 5 ohms between the door speaker and the suspect door tweeter speaker, and greater than 10,000 ohms between the door speaker and ground?
Yes
INSTALL a new door speaker. REFER to Speaker - Door Speaker - Door. CLEAR any DTCs present. TEST the system for normal operation.
No
REPAIR the circuit in question. CLEAR any DTCs present. TEST the system for normal operation.
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C11 CHECK THE AUDIO SIGNALS TO THE SUSPECT SPEAKER
- Ignition OFF.
- Disconnect: Suspect Speaker.
- Operate the audio system in radio tuner (AM/FM) 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, Speaker - Instrument Panel Speaker - Instrument Panel or Speaker - Parcel Shelf Speaker - Parcel Shelf. CLEAR any DTCs present. TEST the system for normal operation.
No
GO to C12.
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C12 CHECK THE AUDIO SIGNALS TO THE AUDIO DSP MODULE
- Ignition OFF.
- Disconnect: Audio DSP Module C4326a.
- Operate the audio system in radio tuner (AM/FM) mode.
- Measure the AC voltage between the audio DSP module pins, harness side as follows:
- Is a fluctuating AC voltage present?
Yes
GO to C15.
No
GO to C13.
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C13 CHECK THE AUDIO SIGNALS TO THE AUDIO DSP MODULE FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: ACM C2253a (Except Subwoofer Concern) or ACM C2253d (Subwoofer Concern).
- Measure the voltage between the audio DSP module, 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 C14.
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C14 CHECK THE AUDIO SIGNALS TO THE AUDIO DSP MODULE FOR AN OPEN OR SHORT TO GROUND
- Ignition OFF.
- Disconnect: ACM C2253a (Except Subwoofer Concern) or ACM C2253d (Subwoofer Concern).
- Measure the resistance between the audio DSP module, harness side and the ACM, harness side; and between the audio DSP module, harness side and ground as follows:
- Is the resistance less than 5 ohms between the audio DSP module and the ACM, and greater than 10,000 ohms between the audio DSP module and ground?
Yes
GO to C18.
No
REPAIR the circuit in question. CLEAR any DTCs present. TEST the system for normal operation.
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C15 CHECK THE CIRCUITS TO THE SPEAKER FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: Audio DSP Module C4326b (Except Subwoofer Concern) or C4326c (Subwoofer Concern).
- 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. CLEAR any DTCs present. TEST the system for normal operation.
No
GO to C16.
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C16 CHECK THE CIRCUITS TO THE SPEAKER FOR AN OPEN OR SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between the suspect speaker, harness side and the audio DSP module, harness side; and between the suspect speaker, harness side and ground as follows:
- Is the resistance less than 5 ohms between the suspect speaker and the audio DSP module, and greater than 10,000 ohms between the suspect speaker and ground?
Yes
REPAIR the circuit in question. CLEAR any DTCs present. TEST the system for normal operation.
No
GO to C17.
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C17 CHECK FOR CORRECT AUDIO DSP MODULE OPERATION
- Ignition OFF.
- Connect: All Disconnected Connectors.
- Disconnect all the audio DSP module connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the audio DSP module 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 audio DSP module. REFER to Audio Digital Signal Processing (DSP) Module Audio Digital Signal Processing (DSP) Module. 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. REPEAT the self-test.
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C18 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 all 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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