Pinpoint Test X: Poor Quality/Distorted/No Sound From One Or More Speakers (Not All Speakers) - Audiophile
Information and Entertainment System
Pinpoint Tests
Pinpoint Test X: Poor Quality/Distorted/No Sound From One Or More Speakers (Not All Speakers) - Audiophile
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 in the form of an AC voltage. The amplifier boosts the audio signals and sends 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 audio amplifier. In dual-play mode, the RETM mutes the rear speaker output. Make sure the audio system is in single-play mode before diagnosing a speaker concern.
A short to ground or short to voltage in the circuitry to the audio amplifier can 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.
It should also be noted that when the ACM activates the built-in overload protection, DTC B1342 can also be set. The circuit failure must be repaired before DTC B1342 can be cleared.
To enable the audio amplifier, the ACM sends voltage through the enable/clip circuit. The circuit acts as both an output (to enable the amplifier) and an input (to detect an amplifier overload condition). The voltage sent by the ACM passes through a variable resistor in the audio 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: amplifier enabled
- Greater than 8.5 volts: amplifier clipped
An open in the enable/clip circuit causes the speakers 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. In either of these scenarios, the subwoofer should continue to operate correctly, as it utilizes a separate amplifier and enable/clip 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.
B1A01:01-B2965:
This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- Speaker
- Audio amplifier
- RETM (if equipped)
- ACM
PINPOINT TEST X: POOR QUALITY/DISTORTED/NO SOUND FROM ONE OR MORE SPEAKERS (NOT ALL SPEAKERS) - AUDIOPHILE
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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X1 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 with the subwoofer speaker?
Yes
Go To Pinpoint Test D. Pinpoint Test D: The Subwoofer Is Inoperative/Does Not Operate Correctly
No
GO to X2.
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X2 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. TEST the system for normal operation.
No
GO to X3.
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X3 CHECK THE AUDIO AMPLIFIER VOLTAGE
- Ignition OFF.
- Disconnect: Audio Amplifier C3154b.
- Measure the voltage between the audio amplifier C3154b-1, circuit SBP03 (BU/RD), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to X4.
No
VERIFY the Smart Junction Box (SJB) fuse 3 (20A) is OK. If OK, REPAIR the circuit. TEST the system for normal operation. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short.
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X4 CHECK THE AUDIO AMPLIFIER GROUND CIRCUIT FOR CONTINUITY
- Disconnect: Negative Battery Cable.
- Measure the resistance between the audio amplifier C3154b-7, circuit GD114 (BK/BU), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
GO to X5.
No
REPAIR the circuit. TEST the system for normal operation.
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X5 CHECK THE AUDIO SIGNALS TO THE AUDIO AMPLIFIER
- Ignition OFF.
- Connect: Audio Amplifier C3154b.
- Disconnect: Audio Amplifier C3154a.
- 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 X6.
No
If the vehicle is equipped with the family entertainment system and the concern is with a rear speaker, GO to X11.
Otherwise, GO to X14.
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X6 CHECK THE AUDIO AMPLIFIER ENABLE CIRCUIT FOR CORRECT VOLTAGE
- Ignition OFF.
- Disconnect: Audio Amplifier C3154b.
- Operate the audio system in radio tuner (AM/FM) mode.
- Measure the voltage between the audio amplifier C3154b-9, circuit CME27 (YE/VT), harness side and ground.
- Is the voltage between 3.8 and 6.7 volts?
Yes
GO to X9.
No
GO to X7.
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X7 CHECK THE AUDIO AMPLIFIER ENABLE CIRCUIT FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: ACM C290a.
- Ignition ON.
- Measure the voltage between the audio amplifier C3154b-9, circuit CME27 (YE/VT), harness side and ground.
- Is any voltage present?
Yes
REPAIR the circuit. TEST the system for normal operation.
No
GO to X8.
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X8 CHECK THE AUDIO AMPLIFIER ENABLE CIRCUIT FOR AN OPEN OR SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between the audio amplifier C3154b-9, circuit CME27 (YE/VT), harness side and the ACM C290a-7, circuit CME27 (YE/VT); and between the audio amplifier C3154b-9, circuit CME27 (YE/VT), harness side and ground.
- Is the resistance less than 5 ohms between the audio amplifier and the ACM, and greater than 10,000 ohms between the audio amplifier and ground?
Yes
GO to X16.
No
REPAIR the circuit. TEST the system for normal operation.
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X9 CHECK THE SPEAKER CIRCUITS FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: Suspect Speaker.
- 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 X10.
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X10 CHECK THE SPEAKER CIRCUITS 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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X11 CHECK THE AUDIO SIGNALS TO THE RETM
- Ignition OFF.
- Disconnect: RETM C9029.
- Operate the audio system in radio tuner (AM/FM), single-play mode.
- Measure the AC voltage between the RETM C9029-11, circuit VME12 (BN/WH), harness side and the RETM C9029-12, circuit RME12 (BN/BU), harness side.
- Measure the AC voltage between the RETM C9029-27, circuit VME09 (WH/GN), harness side and the RETM C9029-28, circuit RME09 (BN/YE), harness side.
- Is a fluctuating AC voltage present?
Yes
GO to X14.
No
GO to X12.
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X12 CHECK THE AUDIO CIRCUITS TO THE RETM FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: ACM C290a.
- Ignition ON.
- Measure the voltage between the RETM, 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 X13.
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X13 CHECK THE AUDIO CIRCUITS TO THE RETM FOR AN OPEN OR SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between the RETM, harness side and the ACM, harness side; and between the RETM, harness side and ground as follows:
- Are the resistances less than 5 ohms between the RETM and the ACM, and greater than 10,000 ohms between the RETM and ground?
Yes
GO to X14.
No
REPAIR the circuit in question. CLEAR any DTCs present. REPEAT the self-test.
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X14 CHECK THE AUDIO CIRCUITS TO THE AUDIO AMPLIFIER FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: ACM C290a.
- 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 X15.
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X15 CHECK THE AUDIO CIRCUITS TO THE AUDIO AMPLIFIER FOR AN OPEN OR SHORT TO GROUND
- Ignition OFF.
- For a front speaker concern, measure the resistance between the audio amplifier, harness side and the ACM, harness side; and between the audio amplifier, harness side and ground as follows:
- For a rear speaker concern, measure the resistance between the audio amplifier, harness side and the RETM, harness side; and between the audio amplifier, harness side and ground as follows:
- Are the resistances less than 5 ohms?
Yes
If the vehicle is equipped with the family entertainment system and the concern is with a rear speaker, GO to X17.
Otherwise, GO to X16.
No
REPAIR the circuit in question. CLEAR any DTCs present. TEST the system for normal operation.
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X16 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.
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X17 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) Service and Repair. 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.
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