Pinpoint Test C: Poor Quality/Distorted/No Sound From One Or More Speakers (Not All Speakers)
Information and Entertainment System
Pinpoint Tests
Pinpoint Test C: Poor Quality/Distorted/No Sound From One Or More Speakers (Not All Speakers)
Refer to Wiring Diagram Set 130, Audio System for schematic and connector information. Diagrams By Number
Normal Operation
The Audio Control Module (ACM) directs audio signals to the speakers in the form of a fluctuating AC voltage. The ACM has an overload protection function that protects the ACM if an over-current condition is present. As a result, if there is a short to ground on the circuitry to any of the 4 interior speakers, the ACM mutes the sound to all of the interior speakers. Only the subwoofer (if equipped) continues to produce sound.
- DTC B2965 (Audio System Speaker Circuit Fault) - sets when an open, short to ground, or short to voltage is detected on the front or rear speaker circuits. The ACM checks for faults once every 500 ms during normal operation, or for any duration during the ACM self-test. On vehicles equipped with Audiophile, the front speakers are not checked for opens.
- If a short to ground is present, DTC B1342 may also set. The circuit fault must be repaired before DTC B1342 can be cleared.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Speaker
- ACM
PINPOINT TEST C: POOR QUALITY/DISTORTED/NO SOUND FROM ONE OR MORE SPEAKERS (NOT ALL SPEAKERS)
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 CHECK THE AUDIO SIGNAL TO THE SPEAKERS
- 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 Door Speaker Door Speaker or Quarter Panel Speaker Quarter Panel Speaker. CLEAR any DTCs present. TEST the system for normal operation.
No
GO to C2.
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C2 CHECK THE AUDIO OUTPUT CIRCUITS FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: ACM C240a.
- 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 C3.
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C3 CHECK THE AUDIO OUTPUT CIRCUITS FOR AN OPEN OR SHORT TO GROUND
- Measure the resistance between the ACM, harness side and the suspect speaker, harness side; and between the ACM, harness side and ground as follows:
- Are the resistances less than 5 ohms between the ACM and the suspect speaker, and greater than 10,000 ohms between the ACM and ground?
Yes
GO to C4.
No
REPAIR the circuit in question. CLEAR any DTCs present. TEST the system for normal operation.
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C4 CHECK FOR CORRECT ACM OPERATION
- 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.
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