Pinpoint Test C: Poor Quality/Distorted/No Sound From One Or More Speakers (Not All Speakers) - Base, Mid-Level Sound
Information and Entertainment System
Pinpoint Test C: Poor Quality/Distorted/No Sound From One Or More Speakers (Not All Speakers) - Base, Mid-Level Sound
Refer to Wiring Diagram Set 130 (Fusion/Milan/MKZ, Fusion Hybrid, Milan Hybrid, MKZ Hybrid), Audio System/Navigation 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 an AC voltage. The ACM provides internal circuit protection for shorts to ground or shorts to voltage.
A short to ground or short to voltage in the circuitry to one of the speakers 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 may also be set. The circuit failure must be repaired before DTC B1342 can be cleared.
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.
- DTC B2965 (Audio System Speaker Circuit Fault) - sets when a short to ground, short to voltage, or open is detected on any of the speaker circuits.
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) - BASE, MID-LEVEL SOUND
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)
- 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 a tweeter speaker?
Yes
GO to C2.
No
GO to C5.
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C2 CHECK FOR VOLTAGE TO THE SUSPECT TWEETER SPEAKER
- Ignition OFF.
- Disconnect: Suspect Tweeter Speaker .
- Operate the audio system in radio tuner (AM/FM) mode.
- Measure the AC voltage between the suspect tweeter speaker pin 1 and pin 2, harness side as follows:
- Is a fluctuating AC voltage present?
Yes
INSTALL a new speaker for the suspect tweeter speaker. REFER to Speaker - Door Speaker - Door. CLEAR any DTCs present. TEST the system for normal operation.
No
GO to C3.
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C3 CHECK THE CIRCUITS TO THE SUSPECT TWEETER SPEAKER FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: LF Door Speaker C592b (LH Speaker Concern) or RF Door Speaker C692b (RH Speaker Concern) .
- Ignition ON.
- Measure the voltage between the suspect tweeter 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 C4.
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C4 CHECK THE CIRCUITS TO THE SUSPECT TWEETER SPEAKER FOR AN OPEN OR SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between the suspect tweeter speaker, harness side and the door speaker, harness side; and between the suspect tweeter speaker, harness side and ground as follows:
- Is the resistance less than 5 ohms between the suspect tweeter speaker and the door speaker, and greater than 10,000 ohms between the suspect tweeter 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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C5 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. CLEAR any DTCs present. TEST the system for normal operation.
No
GO to C6.
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C6 CHECK THE CIRCUITS TO THE SUSPECT SPEAKER 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 C7.
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C7 CHECK THE SPEAKER CIRCUITS FOR AN OPEN OR SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between suspect speaker, harness side and the ACM, harness side; and between the suspect speaker, 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 C8.
No
REPAIR the circuit in question. CLEAR any DTCs present. TEST the system for normal operation.
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C8 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) - Fusion, Milan Audio Control Module (ACM) or Audio Control Module (ACM) - MKZ 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 DTC present.
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