Pinpoint Test L: The Audio Digital Signal Processing (DSP) Module Does Not Respond To The Scan Tool

Refer to appropriate SYSTEM WIRING DIAGRAMS article, Module Communications Network for schematic and connector information.

Refer to appropriate SYSTEM WIRING DIAGRAMS article, Audio System/Navigation for schematic and connector information.

Normal Operation 

The audio digital signal processing (DSP) module communicates with the scan tool through the medium speed controller area network (MS-CAN). Circuits VDB06 (GY/OG) (MS-CAN +) and VDB07 (VT/OG) (MS-CAN -) provide the network connection to the DSP module. The DSP module shares the MS-CAN with the instrument cluster (IC), the accessory protocol interface module (APIM), the smart junction box (SJB), the HVAC module (if equipped), the audio control module (ACM), the satellite digital audio receiver system (SDARS) module (if equipped), the rear entertainment module (RETM) (if equipped), the driver seat module (DSM) (if equipped), the power running board module (if equipped), the parking aid module (PAM) (if equipped), the liftgate/trunk module (LTM) (if equipped) and the dual climate control seat module (DCSM) (if equipped). Voltage for the DSP module is provided by circuits SBP38 (BN/RD) and SBP18 (YE/RD). Circuit GD148 (BK/YE) provides ground.

This pinpoint test is intended to diagnose the following:

• Fuse
• Wiring, terminals or connectors
• DSP module

PINPOINT TEST L: THE AUDIO DIGITAL SIGNAL PROCESSING (DSP) MODULE DOES NOT RESPOND TO THE SCAN TOOL 

1. L1 CHECK THE DSP MODULE VOLTAGE SUPPLY CIRCUITS FOR AN OPEN 
   • Key in OFF position.
   • Disconnect: DSP Module C4348c
   • Key in ON position.
   • Measure the voltage between the DSP module, harness side and ground as follows:

     Connector-Pin	Circuit
     C4348c-9	SBP38 (BN/RD)
     C4348c-10	SBP38 (BN/RD)
     C4348c-11	SBP18 (YE/RD)
     C4348c-12	SBP18 (YE/RD)

   • Are the voltages greater than 10 volts? 
   1. YES  : Go to  L2.
   2. NO  : VERIFY the SJB fuse 38 (20A) or fuse 18 (20A) is OK. If OK, REPAIR the circuit in question. CLEAR the DTCs. REPEAT the network test with the scan tool.
2. L2 CHECK THE DSP MODULE GROUND CIRCUITS FOR AN OPEN 
   • Key in OFF position.
   • Measure the resistance between the DSP module, harness side and ground as follows:

     Connector-Pin	Circuit
     C4348c-22	GD148 (BK/YE)
     C4348c-23	GD148 (BK/YE)
     C4348c-24	GD148 (BK/YE)

   • Are the resistances less than 5 ohms? 
   1. YES  : Go to  L3.
   2. NO  : REPAIR the circuit. CLEAR the DTCs. REPEAT the network test with the scan tool.
3. L3 CHECK THE MS-CAN CIRCUITS BETWEEN THE DSP MODULE AND THE DATA LINK CONNECTOR (DLC) FOR AN OPEN 
   • Disconnect: DSP Module C4348a
   Fig 1: Measuring Resistance
   Courtesy of FORD MOTOR CO.
   • Measure the resistance between the DSP module C4348a-11, circuit VDB06 (GY/OG), harness side and the DLC C251-3, circuit VDB06 (GY/OG), harness side.
   Fig 2: Measuring Resistance
   Courtesy of FORD MOTOR CO.
   • Measure the resistance between the DSP module C4348a-12, circuit VDB07 (VT/OG), harness side and the DLC C251-11, circuit VDB07 (VT/OG), harness side.
   • Are the resistances less than 5 ohms? 
   1. YES  : Go to  L4.
   2. NO  : REPAIR the circuit in question. CLEAR the DTCs. REPEAT the network test with the scan tool.
4. L4 CHECK FOR CORRECT DSP MODULE OPERATION 
   • Disconnect all the DSP module connectors.
   • Check for:
     • corrosion
     • damaged pins
     • pushed-out pins
   • Connect all the DSP module connectors and make sure they seat correctly.
   • Operate the system and verify the concern is still present.
   • Is the concern still present? 
   1. YES  : INSTALL a new DSP module. REFER to INFORMATION AND ENTERTAINMENT SYSTEMS article. 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.