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

WARNING: This page is about a different car, the 2011 Mercury Milan, 2011 Lincoln MKZ, and 2011 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 & CABLES -- FUSION, MILAN & MKZ article.

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:

CONNECTOR-PIN 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: Measuring Voltage Between Audio DSP Module, Harness Side And Ground

Courtesy of FORD MOTOR CO.

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

CONNECTOR-PIN REFERENCE TABLE

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

Fig 2: Measuring Voltage Between Audio DSP Module, Harness Side And Ground

Courtesy of FORD MOTOR CO.

Are the voltages greater than 10 volts?

Yes : GO to W2 .
No : VERIFY the Smart Junction Box (SJB) fuse 19 (25A) (Sony® sound), or Battery Junction Box (BJB) fuse 20 (20A) or 21 (20A) (THX® sound) is OK. If OK, REPAIR the circuit in question. If not OK, REFER to the 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:

CONNECTOR-PIN REFERENCE TABLE

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

Fig 3: Measuring Resistance Between Audio DSP Module, Harness Side And Ground

Courtesy of FORD MOTOR CO.

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

CONNECTOR-PIN REFERENCE TABLE

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

Fig 4: Measuring Resistance Between Audio DSP Module, Harness Side And Ground

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 Medium Speed CAN circuits:
  - For THX® sound, audio DSP module C4235c-11 and the DLC C251-3, circuit VDB06 (GY/OG), harness side.
  - For THX® sound, audio DSP module C4235c-1 and the DLC C251-11, circuit VDB07 (VT/OG), harness side.
  - For Sony® sound, audio DSP module C4240c-1 and the DLC C251-3, circuit VDB06 (GY/OG), harness side.
  - For Sony® sound, audio DSP module C4240c-11 and the DLC C251-11, circuit VDB07 (VT/OG), harness side.
    
    Fig 5: Measuring Resistance Between Medium Speed CAN Circuits
    Courtesy of FORD MOTOR CO.
- Are the resistances less than 5 ohms?
1. Yes : CONNECT the negative battery cable. GO to W4 .
2. 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?
1. Yes : INSTALL a new audio DSP module. REFER to INFORMATION & ENTERTAINMENT SYSTEMS -- FUSION, MILAN & MKZ 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.