Pinpoint Test C: Poor Quality/Distorted/No Sound From One Or More Speakers (Not All Speakers) - Except Subwoofers
Information and Entertainment System
Pinpoint Tests
Pinpoint Test C: Poor Quality/Distorted/No Sound From One Or More Speakers (Not All Speakers) - Except Subwoofers
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 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.
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.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Speaker
- Audio amplifier (navigation only)
- ACM
PINPOINT TEST C: POOR QUALITY/DISTORTED/NO SOUND FROM ONE OR MORE SPEAKERS (NOT ALL SPEAKERS) - EXCEPT SUBWOOFERS
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, Mounting and Cables Service and Repair.
-------------------------------------------------
C1 CHECK THE AUDIO SIGNAL 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 pin 1 and pin 2, harness side as follows:
- Is an alternating AC voltage present?
Yes
INSTALL a new speaker for the suspect speaker. REFER to the appropriate speaker procedure. CLEAR any DTCs present. TEST the system for normal operation.
No
For vehicles with navigation, GO to C2.
For vehicles without navigation, GO to C10.
-------------------------------------------------
C2 CHECK THE AUDIO AMPLIFIER VOLTAGE SUPPLY
- Ignition OFF.
- Disconnect: Audio Amplifier C4364b .
- Measure the voltage between the audio amplifier C4364b-1, circuit SBP19 (BU/RD), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to C3.
No
VERIFY the SJB fuse 19 (25A) 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. Diagrams By Number
-------------------------------------------------
C3 CHECK THE AUDIO AMPLIFIER GROUND FOR CONTINUITY
- Disconnect: Negative Battery Cable.
- Measure the resistance between the audio amplifier C4364b-7, circuit GD173 (BK), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
GO to C4.
No
REPAIR the circuit. CLEAR any DTCs present. TEST the system for normal operation.
-------------------------------------------------
C4 CHECK THE AUDIO 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 audio amplifier C4364b-9, circuit CME31 (BU/GN), harness side and ground.
- Is the voltage between 3.8 and 6.7 volts?
Yes
GO to C7.
No
GO to C5.
-------------------------------------------------
C5 CHECK THE AUDIO AMPLIFIER ENABLE CIRCUIT FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: ACM C290d.
- Ignition ON.
- Measure the voltage between the audio amplifier C4364b-9, circuit CME31 (BU/GN), harness side and ground.
- Is any voltage present?
Yes
REPAIR the circuit. TEST the system for normal operation.
No
GO to C6.
-------------------------------------------------
C6 CHECK THE AUDIO AMPLIFIER ENABLE CIRCUIT FOR AN OPEN OR SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between the ACM C290d-7, circuit CME31 (BU/GN), harness side and the audio amplifier C4364b-9, circuit CME31 (BU/GN), harness side; and between the ACM C290d-7, circuit CME31 (BU/GN), harness side and ground.
- Is the resistance less than 5 ohms between the ACM and the audio amplifier, and greater than 10,000 ohms between the ACM and ground?
Yes
GO to C7.
No
REPAIR the circuit. TEST the system for normal operation.
-------------------------------------------------
C7 CHECK THE AUDIO SIGNALS TO THE AUDIO AMPLIFIER
- Connect: ACM C290d.
- Disconnect: Audio Amplifier C4364a .
- 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 C10.
No
GO to C8.
-------------------------------------------------
C8 CHECK THE AUDIO CIRCUITS TO THE AUDIO AMPLIFIER FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: ACM C290d.
- 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 C9.
-------------------------------------------------
C9 CHECK THE AUDIO CIRCUITS TO THE AUDIO AMPLIFIER FOR AN OPEN OR SHORT TO GROUND
- Ignition OFF.
- 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:
- 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 C12.
No
REPAIR the circuit in question. CLEAR any DTCs present. TEST the system for normal operation.
-------------------------------------------------
C10 CHECK THE SPEAKER CIRCUITS FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: ACM C290d.
- Connect: Audio Amplifier C4364a.
- Connect: Audio Amplifier C4364b.
- 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 C11.
-------------------------------------------------
C11 CHECK THE SPEAKER CIRCUITS FOR AN OPEN OR SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between the suspect speaker, harness side and the ACM (vehicles without navigation) or the audio amplifier (vehicles with navigation) harness side; and between the suspect speaker, harness side and ground as follows:
- Are the resistances less than 5 ohms between the suspect speaker and the ACM (vehicles without navigation) or the audio amplifier (vehicles with navigation), and greater than 10,000 ohms between the suspect speaker and ground?
Yes
For vehicles with navigation, INSTALL a new audio amplifier. REFER to Audio Amplifier Audio Amplifier. CLEAR any DTCs present. TEST the system for normal operation.
For vehicles without navigation, GO to C12.
No
REPAIR the circuit in question. CLEAR any DTCs present. TEST the system for normal operation.
-------------------------------------------------
C12 CHECK FOR CORRECT ACM OPERATION
- 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.
-------------------------------------------------