Pinpoint Test G: Poor Quality/Distorted/No Sound From All Speakers - Sony(R) Sound
Information and Entertainment System
Pinpoint Tests
Pinpoint Test G: Poor Quality/Distorted/No Sound From All Speakers - Sony(R) Sound
Refer to Wiring Diagram Set 130, Audio System/Navigation for schematic and connector information. Diagrams By Number
Normal Operation
The Remote Function Actuator (RFA) module sends a voltage signal to the Audio Control Module (ACM) when the ignition is in a START sequence. This prevents voltage spikes from creating a popping sound during engine cranking. However, if this circuit has a short to voltage or the RFA module sends the signal incorrectly, it results in the speaker output being continuously muted.
To enable the audio Digital Signal Processing (DSP) module, 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 DSP module, then to ground. As the audio DSP module 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 voltage, as detected by the ACM:
- 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 audio system to produce no sound because the enable signal does not reach the audio DSP module. A short to ground or short to voltage can cause severe distortion to be heard in all of the speakers.
- DTC B125C:11 (Radio Mute Circuit: Short to Ground) - sets when the RFA module detects a short to ground on the mute circuit. This should not cause any observable audio system symptoms.
- DTC B125C:15 (Radio Mute Circuit: Short to Battery or Open) - sets when the RFA module detects an open or short to voltage on the mute circuit. If a short to voltage exists, the ACM does not enable the audio DSP module.
This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- Audio DSP module
- ACM
PINPOINT TEST G: POOR QUALITY/DISTORTED/NO SOUND FROM ALL SPEAKERS - SONY(R) 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. Refer to Battery.
-------------------------------------------------
G1 CHECK THE START SENSE SIGNAL TO THE ACM
- Ignition OFF.
- Disconnect: ACM C240a.
- Ignition ON.
- Measure the voltage between the ACM C240a-15, circuit CBP28 (GY/VT), harness side and ground.
- Is any voltage present?
Yes
GO to G2.
No
GO to G3.
-------------------------------------------------
G2 CHECK THE START SENSE CIRCUIT FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: RFA Module C2153d.
- Measure the voltage between the ACM C240a-15, circuit CBP28 (GY/VT), harness side and ground.
- Is any voltage present?
Yes
REPAIR the circuit. CLEAR any DTCs present. TEST the system for normal operation.
No
INSTALL a new RFA module. REFER to Body Control Systems. TEST the system for normal operation.
-------------------------------------------------
G3 CHECK THE START SENSE CIRCUIT FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: RFA Module C2153d.
- Measure the resistance between the ACM C240a-15, circuit CBP28 (GY/VT), harness side and ground.
- Is the resistance greater than 10,000 ohms
Yes
GO to G4.
No
REPAIR the circuit. CLEAR any DTCs present. TEST the system for normal operation.
-------------------------------------------------
G4 CHECK THE AUDIO DSP MODULE VOLTAGE SUPPLY
- Ignition OFF.
- Connect: RFA Module C2153d.
- Disconnect: Audio DSP Module C4326c.
- Measure the voltage between the audio DSP module C4326c-5, circuit SBP19 (BU/RD), harness side and ground; and between the audio DSP module C4326c-6, circuit SBP19 (BU/RD), harness side and ground.
- Are the voltages greater than 10 volts?
Yes
GO to G5.
No
VERIFY the Smart Junction Box (SJB) fuse 19 (25A) is OK. If OK, REPAIR the circuit in question. 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
-------------------------------------------------
G5 CHECK THE AUDIO DSP MODULE GROUND CIRCUITS FOR CONTINUITY
- Disconnect: Negative Battery Cable.
- Measure the resistance between the audio DSP module C4326c-13, circuit GD149 (BK/GY), harness side and ground; and between the audio DSP module C4326c-14, circuit GD149 (BK/GY), harness side and ground.
- Are the resistances less than 5 ohms?
Yes
GO to G6.
No
REPAIR the circuit in question. TEST the system for normal operation.
-------------------------------------------------
G6 CHECK THE AUDIO DSP MODULE ENABLE CIRCUIT FOR CORRECT VOLTAGE
- Connect: Negative Battery Cable.
- Connect: Audio DSP Module C4326c.
- Disconnect: Audio DSP Module C4326a.
- Operate the audio system in radio tuner (AM/FM) mode.
- Measure the voltage between the audio DSP module C4326a-3, circuit SME23 (VT/RD), harness side and ground.
- Is the voltage between 3.8 and 6.7 volts?
Yes
GO to G10.
No
GO to G7.
-------------------------------------------------
G7 CHECK THE AUDIO DSP MODULE ENABLE CIRCUIT FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: ACM C240d.
- Ignition ON.
- Measure the voltage between the audio DSP module C4326a-3, 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 G8.
-------------------------------------------------
G8 CHECK THE AUDIO DSP MODULE ENABLE CIRCUIT FOR AN OPEN OR SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between the audio DSP module C4326a-3, circuit SME23 (VT/RD), harness side and the ACM C240d-4, circuit SME23 (VT/RD), harness side; and between the audio DSP module C4326a-3, circuit SME23 (VT/RD), harness side and ground.
- Is the resistance less than 5 ohms between the audio DSP module and the ACM, and greater than
10,000 ohms between the audio DSP module and ground?
Yes
GO to G9.
No
REPAIR the circuit. TEST the system for normal operation.
-------------------------------------------------
G9 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.
-------------------------------------------------
G10 CHECK FOR CORRECT AUDIO DSP MODULE OPERATION
- Ignition OFF.
- Connect: All Disconnected Connectors.
- Disconnect all the audio DSP module connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the audio DSP 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 audio DSP module. REFER to Audio Digital Signal Processing (DSP) Module Audio Digital Signal Processing (DSP) Module. 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.
-------------------------------------------------