Pinpoint Test L: The Audio Unit Does Not Respond To The Diagnostic Tool

WARNING: This page is about a different car, the 2006 Mercury Milan, 2006 Lincoln Zephyr, and 2006 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.

CAUTION: Use the correct probe adaptor(s) when making measurements. Failure to use the correct probe adaptor(s) may damage the connector.

L1 CHECK THE AUDIO UNIT CONNECTOR FOR DAMAGE
- Key in OFF position.
- Disconnect: Audio Unit C290b or THXII Audio Unit C240c (if equipped).
- Inspect the audio unit connector for damage.
- Is the audio unit connector OK?
Yes : GO to L2.

No : REPAIR the audio unit connector as necessary. CONNECT the audio unit C290b or THXII audio unit C240c (if equipped). CARRY OUT the data link diagnostics test.
L2 CHECK THE MEDIUM SPEED CAN CIRCUITS BETWEEN THE DLC AND THE AUDIO UNIT FOR AN OPEN
- Measure the resistance between the audio unit C290b-15 or THXII audio unit C240c-15, circuit VDB06 (GY/OG), harness side and the DLC C251-3, circuit VDB06 (GY/OG), harness side.
  
  Fig 1: Checking Medium Speed CAN Circuits Between DLC And Audio Unit For Open (1 Of 2)
  Courtesy of FORD MOTOR CO.
- Measure the resistance between the audio unit C290b-16 or THXII audio unit C240c-16, circuit VDB07 (VT/OG), harness side and the DLC C251-11, circuit VDB07 (VT/OG), harness side.
  
  Fig 2: Checking Medium Speed CAN Circuits Between DLC And Audio Unit For Open (2 Of 2)
  Courtesy of FORD MOTOR CO.
- Are the resistances less than 5 ohms?
Yes : GO to L3.

No : REPAIR the circuit. CONNECT the audio unit connector. CARRY OUT the data link diagnostics test.
L3 CHECK FOR CORRECT AUDIO UNIT OPERATION
- Disconnect all the audio unit connectors.
- Check for:
  - Corrosion
  - Pushed-out pins
- Connect all the audio unit 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 unit. REFER to ENTERTAINMENT SYSTEM - GENERAL INFORMATION . CLEAR the diagnostic trouble codes (DTCs). REPEAT the self-test. CARRY OUT the data link diagnostics test.

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 self-test. CARRY OUT the data link diagnostics test.