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

WARNING: This page is about a different car, the 2010 Mercury Milan, 2010 Lincoln MKZ, and 2010 Ford Fusion. 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 will result in false resistance readings. Refer to BATTERY, MOUNTING AND CABLES .

W1 CHECK THE AUDIO DSP MODULE VOLTAGE SUPPLY CIRCUITS FOR AN OPEN

Ignition OFF.
Disconnect: Audio DSP Module C4235a (THX®) or C4240a (Sony®).
Ignition ON.

For THX® sound, measure the voltage between the audio DSP module, harness side and ground as follows:

VOLTAGE REFERENCE TABLE

Connector-Pin	Circuit
C4235a-9	SBB20 (GN/RD)
C4235a-10	SBB20 (GN/RD)
C4235a-11	SBB21 (GY/RD)
C4235a-12	SBB21 (GY/RD)

Fig 1: Checking Audio DSP Module Voltage Supply Circuits For An Open (1 Of 2)

Courtesy of FORD MOTOR CO.

For Sony® sound, measure the voltage between the audio DSP module, harness side and ground as follows:

VOLTAGE REFERENCE TABLE

Connector-Pin	Circuit
C4240a-5	SBP19 (BU/RD)
C4240a-6	SBP19 (BU/RD)

Fig 2: Checking Audio DSP Module Voltage Supply Circuits For An Open (2 Of 2)

Courtesy of FORD MOTOR CO.

Are the voltages greater than 10 volts?

Yes : GO to W2.
No : VERIFY the Battery Junction Box (BJB) fuse 19 (25A), 20 (20A) or 21 (20A) is OK. If OK, REPAIR the circuit in question. If not OK, REFER to the appropriate SYSTEM WIRING DIAGRAMS article to identify the possible causes of the short circuit. CLEAR the DTCs. REPEAT the network test with the scan tool.

W2 CHECK THE AUDIO DSP MODULE GROUND CIRCUITS FOR AN OPEN

Ignition OFF.
Disconnect: Negative Battery Cable.

For THX® sound, measure the resistance between the audio DSP module, harness side and ground as follows:

RESISTANCE REFERENCE TABLE

Connector-Pin	Circuit
C4235a-22	GD148 (BK/YE)
C4235a-23	GD148 (BK/YE)
C4235a-24	GD148 (BK/YE)

Fig 3: Checking Audio DSP Module Ground Circuits For An Open (1 Of 2)

Courtesy of FORD MOTOR CO.

For Sony® sound, measure the resistance between the audio DSP module, harness side and ground as follows:

RESISTANCE REFERENCE TABLE

Connector-Pin	Circuit
C4240a-13	GD148 (BK/YE)
C4240a-14	GD148 (BK/YE)

Fig 4: Checking Audio DSP Module Ground Circuits For An Open (2 Of 2)

Courtesy of FORD MOTOR CO.

Are the resistances less than 5 ohms?

Yes : GO to W3.
No : REPAIR the circuit. CONNECT the negative battery cable. CLEAR the DTCs. REPEAT the network test with the scan tool.

W3 CHECK THE MS-CAN CIRCUITS BETWEEN THE AUDIO DSP MODULE AND THE DLC FOR AN OPEN
- Disconnect: Audio DSP Module C4235c (THX®) or C4240c (Sony®).
- Measure the resistance between the audio DSP module C4235c-11 or C4240c-11, circuit VDB06 (GY/OG), harness side and the DLC C251-3, circuit VDB06 (GY/OG), harness side.
  
  Fig 5: Checking MS-CAN Circuits Between Audio DSP Module And DLC For An Open (1 Of 2)
  Courtesy of FORD MOTOR CO.
- Measure the resistance between the audio DSP module C4235c-1 or C4240c-1, circuit VDB07 (VT/OG), harness side and the DLC C251-11, circuit VDB07 (VT/OG), harness side.
  
  Fig 6: Checking MS-CAN Circuits Between Audio DSP Module And DLC For An Open (2 Of 2)
  Courtesy of FORD MOTOR CO.
- Are the resistances less than 5 ohms?
- Yes : CONNECT the negative battery cable. GO to W4.
- No : REPAIR the circuit in question. CONNECT the negative battery cable. CLEAR the DTCs. REPEAT the network test with the scan tool.
W4 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 seat correctly.
Operate the system and verify the concern is still present.
Is the concern still present?

Yes : INSTALL a new audio DSP module. REFER to INFORMATION AND ENTERTAINMENT SYSTEMS . CLEAR the DTCs. REPEAT the network test with the scan tool.
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.