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Pinpoint Test I : The ACM (Audio Front Control Module) Does Not Respond To The Diagnostic Scan Tool

WARNING: This page is about a different car, the 2020 Ford Transit Connect. However, it is still accessible from the selected car via links, so may be relevant.
  1. Refer to Module Communications Network for schematic and connector information. Audio System/Navigation - AM/FM/CD for schematic and connector information.

    Normal Operation and Fault Conditions 

    The ACM communicates on the HS-CAN3. REFER to: Communications Network - System Operation and Component Description .

    Possible Sources 

    • Fuse
    • Wiring, terminals and connector
    • ACM

    Visual Inspection and Pre-checks 

    • Verify BCM fuse 23 (20A) is OK.

  2. NOTE: Failure to disconnect the battery when instructed will result in false resistance readings.

  3. I1 CHECK THE ACM (AUDIO FRONT CONTROL MODULE) VOLTAGE SUPPLY CIRCUIT FOR AN OPEN

    • Ignition OFF.

    • Disconnect: ACM C240A.

    • Ignition ON.

    • Measure:
      Positive Lead Measurement / Action Negative Lead
      C240A-1
      GFD455923Courtesy of FORD MOTOR COMPANY
      		 Ground

    Is the voltage greater than 11 volts? 

    Yes  GO to  I2
    No  VERIFY the BCM fuse 23 (20A) is OK. If OK, REPAIR the circuit. If not OK, REFER to OEM Electrical Wiring Diagram Introduction to identify the possible causes of the circuit short.

  4. I2 CHECK THE ACM (AUDIO FRONT CONTROL MODULE) GROUND CIRCUIT FOR AN OPEN

    • Ignition OFF.

    • Measure:
      Positive Lead Measurement / Action Negative Lead
      C240A-4
      GFD455922Courtesy of FORD MOTOR COMPANY
      		 Ground

    Is the resistance less than 3 ohms? 

    Yes  GO to  I3
    No  REPAIR the circuit.

  5. I3 CHECK THE HS-CAN3 (HIGH-SPEED CONTROLLER AREA NETWORK 3) CIRCUITS BETWEEN THE ACM (AUDIO FRONT CONTROL MODULE) AND THE GWM (GATEWAY MODULE A) FOR AN OPEN

    • Disconnect GWM C2431.

    Are the resistances less than 3 ohms? 

    Yes  CONNECT the GWM, GO to  I4
    No  REPAIR the circuit in question.

  6. I4 CHECK FOR CORRECT ACM (AUDIO FRONT CONTROL MODULE) OPERATION

    • Ignition OFF.

    • Disconnect and inspect all the ACM connectors.

    • Repair:

      • corrosion (install new connector or terminals - clean module pins)
      • damaged or bent pins - install new terminals/pins
      • pushed-out pins - install new pins as necessary

    • Reconnect the ACM connectors. Make sure they seat and latch correctly.

    • Operate the system and determine if the concern is still present.

    Is the concern still present? 

    Yes  CHECK OASIS for any applicable service articles: TSB, General Service Bulletin (GSB), SSM or FSA. If a service article exists for this concern, DISCONTINUE this test and FOLLOW the service article instructions. If no service articles address this concern, INSTALL a new ACM. REFER to the appropriate Information and Entertainment system article .
    No  The system is operating correctly at this time. The concern may have been caused by module connections. ADDRESS the root cause of any connector or pin issues.
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