Pinpoint Test L: The Audio DSP Module Does Not Respond To The Scan Tool

WARNING: This page is about a different car, the 2014 Lincoln MKX and 2014 Ford Edge. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: 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. Refer to BATTERY, MOUNTING AND CABLES .

L1 CHECK THE AUDIO DSP MODULE VOLTAGE SUPPLY CIRCUITS FOR AN OPEN
- Ignition OFF.
- Disconnect: Audio DSP Module C4348C (THX® System) or C4326C (Sony® System).
- Ignition ON.
- For THX® system, measure the voltage between the audio DSP module C4348C-11 , circuit SBP19 (BU/RD), harness side and ground; and between the audio DSP module C4348C-12 , circuit SBP19 (BU/RD), harness side and ground.
  
  Fig 1: Measuring Voltage Between Audio DSP Module C4348C-11, Circuit SBP19 (BU/RD), Harness Side And Ground
  Courtesy of FORD MOTOR CO.
- For Sony® system, measure the voltage between the audio DSP module C4326C-7 , circuit SBP19 (BU/RD), harness side and ground; and between the audio DSP module C4326C-8 , circuit SBP19 (BU/RD), harness side and ground.
  
  Fig 2: Measuring Voltage Between Audio DSP Module C4326C-7, Circuit SBP19 (BU/RD), Harness Side And Ground
  Courtesy of FORD MOTOR CO.
  
  Are the voltages greater than 10 volts?
  1. Yes : GO to L2.
  2. No : VERIFY the BCM fuse 19 (20A) is OK. If OK, REPAIR the circuit in question. If not OK, REFER to the SYSTEM WIRING DIAGRAMS to identify the possible causes of the circuit short. CLEAR the DTCs. REPEAT the network test with the scan tool.
L2 CHECK THE AUDIO DSP MODULE GROUND CIRCUITS FOR AN OPEN
- Ignition OFF.
- Disconnect: Negative Battery Cable.
- For the THX® system, measure the resistance between the audio DSP module C4348C-21 , circuit GD148 (BK/YE), harness side and ground; and between the audio DSP module C4348C-22 , circuit GD148 (BK/YE), harness side and ground.
  
  Fig 3: Measuring Resistance Between Audio DSP Module C4348C-21, Circuit GD148 (BK/YE), Harness Side And Ground
  Courtesy of FORD MOTOR CO.
- For the Sony® system measure, the resistance between the audio DSP module C4326C-13 , circuit GD148 (BK/YE), harness side and ground; and between the audio DSP module C4326C-14 , circuit GD148 (BK/YE), harness side and ground.
  
  Fig 4: Measuring Resistance Between Audio DSP Module C4326C-13, Circuit GD148 (BK/YE), Harness Side And Ground
  Courtesy of FORD MOTOR CO.
  
  Are the resistances less than 5 ohms?
  1. Yes : GO to L3.
  2. No : REPAIR the circuit in question. CONNECT the negative battery cable. CLEAR the DTCs. REPEAT the network test with the scan tool.
L3 CHECK THE I-CAN CIRCUITS BETWEEN THE AUDIO DSP MODULE AND THE IPC FOR AN OPEN
- Disconnect: IPC C220 .
- Disconnect: Audio DSP Module C4348A (THX® System) C4326A (Sony® System).
- For the THX® system, measure the resistance between the audio DSP module C4348A-11 , circuit VDB13 (BU/GY), harness side and the IPC C220-25 , circuit VDB13 (BU/GY), harness side.
  
  Fig 5: Measuring Resistance Between Audio DSP Module C4348A-11, Circuit VDB13 (BU/GY) And IPC C220-25, Circuit VDB13 (BU/GY), Harness Side
  Courtesy of FORD MOTOR CO.
- For the THX® system, measure the resistance between the audio DSP module C4348A-1 , circuit VDB14 (VT/GY), harness side and the IPC C220-26 , circuit VDB14 (VT/GY), harness side.
  
  Fig 6: Measuring Resistance Between Audio DSP Module C4348A-1, Circuit VDB14 (VT/GY) And IPC C220-26, Circuit VDB14 (VT/GY), Harness Side
  Courtesy of FORD MOTOR CO.
- For the Sony® system, measure the resistance between the audio DSP module C4346A-1 , circuit VDB13 (BU/GY), harness side and the IPC C220-25 , circuit VDB13 (BU/GY), harness side.
  
  Fig 7: Measuring Resistance Between Audio DSP Module C4346A-1, Circuit VDB13 (BU/GY) And IPC C220-26, Circuit VDB14 (VT/GY), Harness Side
  Courtesy of FORD MOTOR CO.
- For the Sony® system, measure the resistance between the audio DSP module C4346A-11 , circuit VDB14 (VT/GY), harness side and the IPC C220-26 , circuit VDB14 (VT/GY), harness side.
  
  Fig 8: Measuring Resistance Between Audio DSP Module C4346A-11, Circuit VDB14 (VT/GY) And IPC C220-26, Circuit VDB14 (VT/GY), Harness Side
  Courtesy of FORD MOTOR CO.
  
  Are the resistances less than 5 ohms?
  1. Yes : CONNECT the negative battery cable. GO to L4.
  2. No : REPAIR the circuit in question. CONNECT the negative battery cable. CLEAR the DTCs. REPEAT the network test with the scan tool.
L4 CHECK FOR CORRECT AUDIO DSP MODULE OPERATION
- 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 are seated correctly.
- Operate the system and verify the concern is still present.
  Is the concern still present?
  1. Yes : INSTALL a new audio DSP module. REFER to INFORMATION AND ENTERTAINMENT SYSTEMS . CLEAR the DTCs.
    REPEAT the network test with the scan tool.
  2. No : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the network test with the scan tool.