Pinpoint Test D: No Sound From All Speakers
Information and Entertainment System
Pinpoint Test D: No Sound From All Speakers
Refer to Wiring Diagram Set 130, Audio System/Navigation for schematic and connector information Electrical Diagrams.
Normal Operation - Base and Edge Premium Audio
When the key is in START, the Audio Control Module (ACM) receives voltage on the START signal circuit. The ACM (Audio Control Module) then mutes the speaker output to prevent voltage spikes from producing a popping noise through the speakers. However, a short to voltage on this circuit causes the ACM (Audio Control Module) output to be continuously muted.
If a speaker circuit fault DTC is set in the ACM (Audio Control Module), the cause of the concern is a short to ground or short to voltage in an individual speaker circuit, which has caused the ACM (Audio Control Module) overload protection to activate. If a speaker circuit fault DTC is present, refer to DTC Charts Accessories and Optional Equipment.
Normal Operation - MKX Premium Audio
When the key is in START, the Audio Control Module (ACM) receives voltage on the START signal circuit. The ACM (Audio Control Module) then mutes the speaker output to prevent voltage spikes from producing a popping noise through the speakers. However, a short to voltage on this circuit causes the ACM (Audio Control Module) output to be continuously muted.
Normal Operation - THX(R) and Sony(R) Audio
When the key is in START, the ACM (Audio Control Module) receives voltage on the START signal circuit. The ACM (Audio Control Module) then mutes the speaker output to prevent voltage spikes from producing a popping noise through the speakers. However, a short to voltage on this circuit causes the ACM (Audio Control Module) output to be continuously muted.
The audio Digital Signal Processing (DSP) module is enabled through software. Additionally, the ACM (Audio Control Module) can mute the audio DSP (Digital Signal Processing) module through the mute/unmute circuit. If the audio DSP (Digital Signal Processing) module detects less than 3.5 volts on the mute/unmute circuit, it mutes the speaker output. As a result, an open or short to ground in the mute/unmute circuit causes the audio system to produce no sound, because the enable signal does not reach the audio DSP (Digital Signal Processing) module.
In the event of an overload, the audio DSP (Digital Signal Processing) module clips the audio output signal to the speakers and subwoofer (heard as distortion) in order to prevent damage to the speakers.
This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- Audio amplifier (MKX premium audio)
- Audio DSP (Digital Signal Processing) module (Sony(R) or THX(R) audio)
- ACM (Audio Control Module)
PINPOINT TEST D : NO SOUND FROM ALL SPEAKERS
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 results in false resistance readings.
D1 CHECK THE START SIGNAL 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-3, circuit CDC26 (GY/OG), harness side and ground.
Is any voltage present?
Yes
REPAIR the circuit. TEST the system for normal operation.
No
For base or Edge Premium audio, GO to D8.
For MKX Premium audio, GO to D2.
For all other audio systems, GO to D3.
D2 CHECK THE SUBWOOFER OPERATION
- Ignition OFF.
- Connect: ACM (Audio Control Module) C240A.
- Operate the audio system in radio tuner (AM/FM) mode and observe the operation of the subwoofer.
Does the subwoofer produce sound?
Yes
GO to D3.
No
GO to D8.
D3 CHECK THE AUDIO AMPLIFIER OR AUDIO DSP (Digital Signal Processing) MODULE VOLTAGE SUPPLY
- Ignition OFF.
- Disconnect: Audio DSP (Digital Signal Processing) Module C4326C (Sony(R) Audio).
- Disconnect: Audio Amplifier C4364B (MKX Premium Audio).
- Disconnect: Audio DSP (Digital Signal Processing) Module C4348C (THX(R) Audio).
- Ignition ON.
- Measure the voltage between the audio amplifier or audio DSP (Digital Signal Processing) module, harness side and ground as follows:
Positive Meter Lead Negative Meter Lead Circuit C4326C-7 (Sony(R) audio) Ground SBP19 (BU/RD) C4326C-8 (Sony(R) audio) Ground SBP19 (BU/RD) C4364B-12 (MKX premium audio) Ground SBP19 (BU/RD) C4364B-24 (MKX premium audio) Ground SBP19 (BU/RD) C4348C-11 (THX(R) audio) Ground SBP19 (BU/RD) C4348C-12 (THX(R) audio) Ground SBP19 (BU/RD)
Are the voltages greater than 10 volts?
Yes
GO to D4.
No
VERIFY the Body Control Module (BCM) fuse 19 (20A) 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.
D4 CHECK THE AUDIO AMPLIFIER OR AUDIO DSP (Digital Signal Processing) MODULE GROUND CIRCUITS FOR CONTINUITY
- Ignition OFF.
- Disconnect: Negative Battery Cable.
- Measure the resistance between the audio amplifier or audio DSP (Digital Signal Processing) module, harness side and ground as follows:
Positive Meter Lead Negative Meter Lead Circuit C4326C-13 (Sony(R) audio) Ground GD148 (BK/YE) C4326C-14 (Sony(R) audio) Ground GD148 (BK/YE) C4364B-21 (MKX premium audio) Ground GD148 (BK/YE) C4364B-22 (MKX premium audio) Ground GD148 (BK/YE) C4348C-21 (THX(R) audio) Ground GD148 (BK/YE) C4348C-22 (THX(R) audio) Ground GD148 (BK/YE)
Are the resistances less than 5 ohms?
Yes
GO to D5.
No
REPAIR the circuit in question. TEST the system for normal operation.
D5 CHECK THE AUDIO AMPLIFIER OR AUDIO DSP (Digital Signal Processing) MODULE ENABLE CIRCUIT FOR CORRECT VOLTAGE
- Connect: Negative Battery Cable.
- Ignition ON.
- Operate the audio system in radio tuner (AM/FM) mode.
- Measure the voltage between the audio DSP (Digital Signal Processing) module C4326A-3 (Sony(R) audio), C4364A-11 (MKX Premium audio) or C4348A-3 (THX(R) audio), circuit SME23 (VT/RD), harness side and ground.
Is the voltage between 3.8 and 6.7 volts (MKX Premium audio), or greater than 3.5 volts (Sony(R) or THX(R) audio)?
Yes
For Sony(R) and THX(R) audio, GO to D9.
For MKX Premium audio, INSTALL a new audio amplifier. REFER to Audio Amplifier . TEST the system for normal operation.
No
GO to D6.
D6 CHECK THE AUDIO AMPLIFIER OR AUDIO DSP (Digital Signal Processing) MODULE ENABLE CIRCUIT FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: ACM (Audio Control Module) C240B.
- Ignition ON.
- Measure the voltage between the audio DSP (Digital Signal Processing) module C4326A-3 (Sony(R) audio), C4364A-11 (MKX Premium audio) or C4348A-3 (THX(R) audio), 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 D7.
D7 CHECK THE AUDIO AMPLIFIER OR AUDIO DSP (Digital Signal Processing) MODULE ENABLE CIRCUIT FOR AN OPEN OR SHORT TO GROUND
- Ignition OFF.
- For Sony(R) audio, measure the resistance between the ACM (Audio Control Module) C240B-18, circuit SME23 (VT/RD), harness side and the audio DSP (Digital Signal Processing) module C4326A-3, circuit SME23 (VT/RD), harness side; and between the ACM (Audio Control Module) C240B-18, circuit SME23 (VT/RD), harness side and ground.
- For MKX Premium audio, measure the resistance between the ACM (Audio Control Module) C240B-18, circuit SME23 (VT/RD), harness side and the audio amplifier C4364A-11, circuit SME23 (VT/RD), harness side; and between the ACM (Audio Control Module) C240B-18, circuit SME23 (VT/RD), harness side and ground.
- For THX(R) audio, measure the resistance between the ACM (Audio Control Module) C240B-18, circuit SME23 (VT/RD), harness side and the audio DSP (Digital Signal Processing) module C4348A-3, circuit SME23 (VT/RD), harness side; and between the ACM (Audio Control Module) C240B-18, circuit SME23 (VT/RD), harness side and ground.
Is the resistance less than 5 ohms between the ACM (Audio Control Module) and the audio amplifier or audio DSP (Digital Signal Processing) module and greater than 10,000 ohms between the ACM (Audio Control Module) and ground?
Yes
GO to D8.
No
REPAIR the circuit. TEST the system for normal operation.
D8 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.
D9 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.