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Pinpoint Test J : The C-Cm Does Not Communicate With The Scan Tool

WARNING: This page is about a different car, the 2018 Lincoln MKT. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: Failure to disconnect the battery when instructed will result in false resistance readings. Refer to Battery, Mounting and Cables .

  1. J1 CHECK THE C-CM VOLTAGE SUPPLY CIRCUITS FOR AN OPEN

    • Ignition OFF.

    • Disconnect: C-CM C1582 .

    • Ignition ON.

    • Measure the voltage  between:
      Positive Lead Negative Lead
      Pin Circuit Pin Circuit
      C1582-10 CBB91 (BN) - Ground

    1. GFD232137Courtesy of FORD MOTOR COMPANY

    Is the voltage greater than 11 volts? 

    Yes  GO to  J2.
    No  VERIFY the Battery Junction Box (BJB) fuse 91 (10A) is OK. If OK, REPAIR the circuit. If not OK, REFER to the OEM ELECTRICAL WIRING DIAGRAM INTRODUCTION to identify the possible causes of the circuit short.

  2. J2 CHECK THE C-CM GROUND CIRCUIT FOR AN OPEN

    • Ignition OFF.

    • Disconnect: Negative Battery Cable.

    • Measure the resistance  between:
      Positive Lead Negative Lead
      Pin Circuit Pin Circuit
      C1582-4 GD123 (BK/GY) - Ground

    1. GFD232137Courtesy of FORD MOTOR COMPANY

    Is the resistance less than 3 ohms? 

    Yes  GO to  J3.
    No  REPAIR the circuit in question.

  3. J3 CHECK THE HS-CAN CIRCUITS BETWEEN THE C-CM AND THE DLC FOR AN OPEN

    • Measure the resistance  between:
      Positive Lead Negative Lead
      Pin Circuit Pin Circuit
      C1582-8 VDB04 (WH/BU) C251-6 VDB04 (WH/BU)
      C1582-7 VDB05 (WH) C251-14 VDB05 (WH)

    1. GFD232143Courtesy of FORD MOTOR COMPANY

    Are the resistances less than 3 ohms? 

    Yes  GO to  J4.
    No  REPAIR the circuit in question.

  4. J4 CHECK FOR CORRECT C-CM OPERATION

    • Disconnect the C-CM connector.

    • Repair:

      • corrosion (replace connector or terminals - clean module pins)

      • damaged or bent pins - replace terminals/pins

      • pushed-out pins - replace pins as necessary

    • Connect the C-CM connector and make sure it seats correctly.

    • Operate the system and verify the concern is still present.

    Is the concern still present? 

    Yes  CHECK OASIS for any applicable TSBs. If a TSB exists for this concern, discontinue this test and follow TSB instructions. If no TSBs address this concern, INSTALL a new C-CM. REFER to Cruise Control Adaptive .
    No  The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.
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