Pinpoint Test E: Poor Quality/Distorted/No Sound From All Speakers - Sony(R) Sound
Information and Entertainment System
Pinpoint Test E: Poor Quality/Distorted/No Sound From All Speakers - Sony(R) Sound
Refer to Wiring Diagrams Set 130, Audio System/Navigation for schematic and connector information. Electrical Diagrams
Normal Operation
When the ignition is in the START position, voltage is supplied to the Audio Control Module (ACM) through the START sense circuit. When the ACM (Audio Control Module) receives this voltage, it mutes the speaker output by removing the enable voltage to the audio Digital Signal Processing (DSP) module. This prevents popping in the speakers as a result of voltage spikes during engine cranking.
If there is a short to voltage on the enable circuit, the ACM (Audio Control Module) continuously mutes the audio output, resulting in no sound from all speakers.
To enable the audio DSP (Digital Signal Processing) module, the ACM (Audio Control Module) 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 (Audio Control Module) passes through a variable resistor in the audio DSP (Digital Signal Processing) module, then to ground. As the audio DSP (Digital Signal Processing) module 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 amplifier (heard as distortion), in order to prevent damage to the amplifier and speakers.
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: 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 (Digital Signal Processing) module. A short to ground or short to voltage can cause severe distortion to be heard in all of the speakers.
This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- Audio DSP (Digital Signal Processing) module
- ACM (Audio Control Module)
PINPOINT TEST E : 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.
E1 CHECK THE START SENSE CIRCUIT FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: ACM (Audio Control Module) C240A.
- Ignition ON.
- Measure the voltage between the ACM (Audio Control Module) C240A-15, circuit CBP28 (GY/VT), harness side and ground.
Is any voltage present?
Yes
REPAIR the circuit. TEST the system for normal operation.
No
GO to E2.
E2 CHECK THE AUDIO DSP (Digital Signal Processing) MODULE VOLTAGE SUPPLY
- Ignition OFF.
- Disconnect: Audio DSP (Digital Signal Processing) Module C4208C.
- Measure the voltage between the audio DSP (Digital Signal Processing) module, harness side and ground as follows:
Positive Meter Lead Negative Meter Lead C4208C-5 SBB07 (WH/RD) Ground C4208C-6 SBB07 (WH/RD) Ground C4208C-7 SBB07 (WH/RD) Ground C4208C-8 SBB07 (WH/RD) Ground
Are the voltages greater than 10 volts?
Yes
GO to E3.
No
VERIFY the Battery Junction Box (BJB) fuse 7 (30A) 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. Electrical Diagrams
E3 CHECK THE AUDIO DSP (Digital Signal Processing) MODULE GROUND CIRCUITS FOR CONTINUITY
- Ignition OFF.
- Disconnect: Negative Battery Cable.
- Measure the resistance between the audio amplifier, harness side and ground as follows:
Positive Meter Lead Negative Meter Lead C4208C-13 GD148 (BK/YE) Ground C4208C-14 GD148 (BK/YE) Ground C4208C-15 GD148 (BK/YE) Ground C4208C-16 GD148 (BK/YE) Ground
Are the resistances less than 5 ohms?
Yes
GO to E4.
No
REPAIR the circuit in question. TEST the system for normal operation.
E4 CHECK THE AUDIO DSP (Digital Signal Processing) MODULE ENABLE CIRCUIT FOR CORRECT VOLTAGE
- Connect: Audio DSP (Digital Signal Processing) Module C4208C.
- Connect: Negative Battery Cable.
- Disconnect: Audio DSP (Digital Signal Processing) Module C4208A.
- Measure the voltage between the audio DSP (Digital Signal Processing) module C4208A-3, circuit SME23 (VT/RD), harness side and ground.
Is the voltage between 0.5 and 8.4 volts?
Yes
GO to E8.
No
GO to E5.
E5 CHECK THE AUDIO DSP (Digital Signal Processing) MODULE ENABLE CIRCUIT FOR A SHORT TO VOLTAGE
- Disconnect: ACM (Audio Control Module) C240B.
- Measure the voltage between the audio DSP (Digital Signal Processing) module C4208A-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 E6.
E6 CHECK THE AUDIO DSP (Digital Signal Processing) MODULE ENABLE CIRCUIT FOR AN OPEN OR SHORT TO GROUND
- Measure the resistance between the audio DSP (Digital Signal Processing) module C4208A-3, circuit SME23 (VT/RD), harness side and the ACM (Audio Control Module) C240B-4, circuit SME23 (VT/RD), harness side; and between the audio DSP (Digital Signal Processing) module C4208A-3, circuit SME23 (VT/RD), harness side and ground.
Is the resistance less than 5 ohms between the audio DSP (Digital Signal Processing) module and the ACM (Audio Control Module), and greater than
10,000 ohms between the audio DSP (Digital Signal Processing) module and ground?
Yes
GO to E7.
No
REPAIR the circuit. TEST the system for normal operation.
E7 CHECK FOR CORRECT ACM (Audio Control Module) OPERATION
- Ignition OFF.
- Connect: All Disconnected Connectors.
- 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.
E8 CHECK FOR CORRECT AUDIO DSP (Digital Signal Processing) MODULE OPERATION
- Ignition OFF.
- Connect: All Disconnected Connectors.
- Disconnect all the audio DSP (Digital Signal Processing) module connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the audio DSP (Digital Signal Processing) 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 (Digital Signal Processing) module. REFER to 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. CLEAR any DTCs present.