Pinpoint Test D: Poor Quality/Distorted/No Sound From One Or More Speakers (Not All Speakers) - Premium Sound
Information and Entertainment System
Pinpoint Test D: Poor Quality/Distorted/No Sound From One Or More Speakers (Not All Speakers) - Premium Sound
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 and to the speakers in the form of an AC voltage. The audio amplifier boosts the audio signals to the instrument panel speaker. The ACM (Audio Control Module) 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 may cause multiple speakers to lose sound due to the built-in overload protection feature of the ACM (Audio Control Module). 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 Service and Repair.
To enable the audio amplifier, the ACM (Audio Control Module) sends voltage through an enable/clip circuit. The circuit acts as both an output (to enable the amplifier) and an input (to detect an overload condition). The voltage sent by the ACM (Audio Control Module) 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 (Audio Control Module) detecting a higher voltage on the enable/clip circuit. When the voltage reaches the clip threshold, the ACM (Audio Control Module) clips the audio output signal to the audio amplifier (heard as distortion), in order to prevent damage to the amplifier and instrument panel speaker.
The enable/clip status is based on the following voltages, as detected by the ACM (Audio Control Module) :
- Less than 0.4 volt: amplifier disabled
- Between 3.8 and 6.7 volts (nominal): amplifier enabled
- Greater than 8.5 volts: amplifier clipped
An open in the enable/clip circuit causes the instrument panel speaker 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 instrument panel speaker.
- 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:
- Fuse
- Wiring, terminals or connectors
- Speaker
- Audio amplifier
- ACM (Audio Control Module)
PINPOINT TEST D : POOR QUALITY/DISTORTED/NO SOUND FROM ONE OR MORE SPEAKERS (NOT ALL SPEAKERS) - PREMIUM SOUND
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.
D1 DETERMINE THE INOPERATIVE SPEAKER(S)
- Carry out the speaker walk test. Refer to Audio Control Module (ACM) Self-Diagnostic Mode Service and Repair.
Is the concern only with the instrument panel speaker?
Yes
GO to D2.
No
If the concern is only with an A-pillar speaker, GO to D13.
For all other concerns, GO to D16.
D2 CHECK THE AUDIO SIGNAL TO THE INSTRUMENT PANEL SPEAKER
- Ignition OFF.
- Disconnect: Instrument Panel Speaker C2359.
- Ignition ON.
- Operate the audio system in radio tuner (AM/FM) mode.
- Measure the AC voltage between the instrument panel speaker C2359-1, circuit VME06 (GN), harness side and the instrument panel speaker C2359-2, circuit RME06 (GY/YE).
Is a fluctuating AC voltage present?
Yes
INSTALL a new instrument panel speaker. REFER to Speaker - Instrument Panel . TEST the system for normal operation.
No
GO to D3.
D3 CHECK THE AUDIO CIRCUITS TO THE INSTRUMENT PANEL SPEAKER FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: Audio Amplifier C4208B.
- Ignition ON.
- Measure the voltage between the instrument panel speaker C2359-1, circuit VME06 (GN), harness side and ground; and between the instrument panel speaker C2359-2, circuit RME06 (GY/YE), harness side.
Is any voltage present?
Yes
REPAIR the circuit in question. TEST the system for normal operation.
No
GO to D4.
D4 CHECK THE AUDIO CIRCUITS TO THE INSTRUMENT PANEL SPEAKER FOR AN OPEN OR SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between the instrument panel speaker, harness side and the audio amplifier, harness side; and between the instrument panel speaker, harness side and ground as follows:
Is the resistance less than 5 ohms between the instrument panel speaker and the audio amplifier, and greater than 10,000 ohms between the instrument panel speaker and ground?
Yes
GO to D5.
No
REPAIR the circuit in question. TEST the system for normal operation.
D5 CHECK THE AUDIO AMPLIFIER VOLTAGE SUPPLY
- Ignition OFF.
- Connect: Audio Amplifier C4208B.
- Disconnect: Audio Amplifier C4208A.
- Measure the voltage between the audio amplifier C4208A-5, circuit SBP38 (BN/RD), harness side and ground; and between the audio amplifier C4208A-4, circuit SBP38 (BN/RD), harness side and ground.
Are the voltages greater than 10 volts?
Yes
GO to D6.
No
VERIFY the Smart Junction Box (SJB) fuse 38 (20A) is OK. If OK, REPAIR the circuit in question. CLEAR any DTCs present. 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
D6 CHECK THE AUDIO AMPLIFIER GROUND CIRCUIT FOR CONTINUITY
- Disconnect: Negative Battery Cable.
- Measure the resistance between the audio amplifier C4208A-2, circuit GD149 (BK/GY), harness side and ground.
Is the resistance less than 5 ohms?
Yes
GO to D7.
No
REPAIR the circuit. CLEAR any DTCs present. TEST the system for normal operation.
D7 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 C4208A-1, circuit SME23 (VT/RD), harness side and ground.
Is the voltage between 3.8 and 6.7 volts?
Yes
GO to D10.
No
GO to D8.
D8 CHECK THE AUDIO AMPLIFIER ENABLE CIRCUIT FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: ACM (Audio Control Module) C240D.
- Ignition ON.
- Measure the voltage between the audio amplifier C4208A-1, circuit SME23 (VT/RD), harness side and ground.
Is any voltage present?
Yes
REPAIR the circuit. TEST the system for normal operation.
No
GO to D9.
D9 CHECK THE AUDIO AMPLIFIER ENABLE CIRCUIT FOR AN OPEN OR SHORT TO GROUND
- Ignition OFF.
- Measure the voltage between the audio amplifier C4208A-1, circuit SME23 (VT/RD), harness side and the ACM (Audio Control Module) C240D-4, circuit SME23 (VT/RD), harness side and ground; and between the audio amplifier C4208A-1, circuit SME23 (VT/RD), harness side and ground.
Is the resistance less than 5 ohms between the audio amplifier and the ACM (Audio Control Module), and greater than 10,000 ohms between the audio amplifier and ground?
Yes
GO to D19.
No
REPAIR the circuit. TEST the system for normal operation.
D10 CHECK THE AUDIO SIGNAL TO THE AUDIO AMPLIFIER
- Operate the audio system in radio tuner (AM/FM) mode.
- Measure the AC voltage between the audio amplifier C4208A-7, circuit VME51 (BN/BU), harness side and the audio amplifier C4208A-8, circuit RME51 (WH/BU), harness side.
Is a fluctuating AC voltage present?
Yes
INSTALL a new audio amplifier. REFER to Audio Amplifier . TEST the system for normal operation.
No
GO to D11.
D11 CHECK THE AUDIO CIRCUITS TO THE AUDIO AMPLIFIER FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Measure the voltage between the audio amplifier C4208A-7, circuit VME51 (BN/BU), harness side ground; and between the audio amplifier C4208A-8, circuit RME51 (WH/BU), harness side and ground.
Is any voltage present?
Yes
REPAIR the circuit in question. CLEAR any DTCs present. TEST the system for normal operation.
No
GO to D12.
D12 CHECK THE AUDIO CIRCUITS TO THE AUDIO AMPLIFIER FOR AN OPEN OR SHORT TO GROUND
- Measure the resistance between the audio amplifier, harness side and the ACM (Audio Control Module), 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 (Audio Control Module), and greater than 10,000 ohms between the audio amplifier and ground?
Yes
GO to D19.
No
REPAIR the circuit in question. CLEAR any DTCs present. TEST the system for normal operation.
D13 CHECK FOR VOLTAGE TO THE SUSPECT A-PILLAR SPEAKER
- Ignition OFF.
- Disconnect: Suspect A-Pillar Speaker.
- Operate the audio system in radio tuner (AM/FM) mode.
- Measure the AC voltage between the suspect A-pillar speaker pin 1 and pin 2, harness side as follows:
Is a fluctuating AC voltage present?
Yes
INSTALL a new speaker for the suspect A-pillar speaker. REFER to Speaker - A-Pillar . CLEAR any DTCs present. TEST the system for normal operation.
No
GO to D14.
D14 CHECK THE CIRCUITS TO THE SUSPECT A-PILLAR SPEAKER FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: LF Door Speaker C523B (LH Speaker Concern) or RF Door Speaker C612B (RH Speaker Concern).
- Ignition ON.
- Measure the voltage between the suspect A-pillar 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 D15.
D15 CHECK THE CIRCUITS TO THE SUSPECT A-PILLAR SPEAKER FOR AN OPEN OR SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between the suspect A-pillar speaker, harness side and the door speaker, harness side; and between the suspect A-pillar speaker, harness side and ground as follows:
Is the resistance less than 5 ohms between the suspect A-pillar speaker and the door speaker, and greater than 10,000 ohms between the suspect A-pillar speaker and ground?
Yes
INSTALL a new door speaker. REFER to 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.
D16 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 . CLEAR any DTCs present. TEST the system for normal operation.
No
GO to D17.
D17 CHECK THE CIRCUITS TO THE SUSPECT SPEAKER FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: ACM (Audio Control Module) 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 D18.
D18 CHECK THE SPEAKER CIRCUITS FOR AN OPEN OR SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between the ACM (Audio Control Module), harness side and the suspect speaker, harness side; and between the ACM (Audio Control Module), harness side and ground as follows:
Are the resistances less than 5 ohms between the ACM (Audio Control Module) and the suspect speaker, and greater than 10,000 ohms between the ACM (Audio Control Module) and ground?
Yes
GO to D19.
No
REPAIR the circuit in question. CLEAR any DTCs present. TEST the system for normal operation.
D19 CHECK FOR CORRECT ACM (Audio Control Module) OPERATION
- Disconnect all the ACM (Audio Control Module) connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the ACM (Audio Control 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 ACM (Audio Control Module). REFER to 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.