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Pinpoint Test C : U0100:87

WARNING: This page is about a different car, the 2020 Ford Mustang. However, it is still accessible from the selected car via links, so may be relevant.
  1. Refer to OEM WIRING DIAGRAMS FOR MODULE COMMUNICATIONS NETWORK for schematic and connector information.

    Normal Operation and Fault Conditions 

    REFER to: Communications Network - System Operation and Component Description .

    DTC Fault Trigger Conditions 

    DTC Description Fault Trigger Condition
    BCM U0100:87 Lost Communication With ECM/PCM "A": Missing Message A continuous memory DTC that sets in the BCM if powertrain data messages received from the PCM are missing.

    Possible Sources 

    • Communication network concern
    • Charging system concern
    • PCM
    • BCM

  2. NOTE: If new modules were installed prior to the DTC being set, the module configuration may be incorrectly set during the PMI or the PMI may not have been carried out.

  3. C1 VERIFY THE DIAGNOSTIC SCAN TOOL COMMUNICATES WITH THE PCM (POWERTRAIN CONTROL MODULE)

    • Ignition ON.

    • Connect the diagnostic tool.

    • Check that a vehicle session can be established using the diagnostic scan tool.

    Can a vehicle session be established? 

    Yes  GO to  C2
    No  REFER to: Communications Network .

  4. C2 RECHECK THE BCM (BODY CONTROL MODULE) CONTINUOUS MEMORY DIAGNOSTIC TROUBLE CODES (CMDTCS)

    • Using a diagnostic scan tool, clear the Diagnostic Trouble Codes (DTCs).

    • Wait 10 seconds.

    • Using a diagnostic scan tool, check the BCM CMDTCs.

    Is DTC U0100:87 present? 

    Yes  GO to  C3
    No  The system is operating correctly at this time. The DTC may have been set due to high network traffic or an intermittent fault condition.

  5. C3 RETRIEVE THE PCM (POWERTRAIN CONTROL MODULE) DTCS

    • Using a diagnostic scan tool, perform the PCM KOEO self-test.

    Are any PCM DTCs present? 

    Yes  Refer to the appropriate Engine article for the procedure.
    No  GO to  C4

  6. C4 RETRIEVE THE BCM (BODY CONTROL MODULE) DTCS FROM THE SELF-TEST

    • Using a diagnostic scan tool, perform the BCM self-test.

    Are any BCM present? 

    Yes  REFER to DTC Chart: BCM  .
    No  GO to  C5

  7. C5 CHECK FOR DTC (DIAGNOSTIC TROUBLE CODE) U0100:87 SET IN OTHER MODULES

    • Using a diagnostic scan tool, clear the DTCs.

    • Ignition OFF.

    • Ignition ON.

    • Wait 10 seconds.

    • Using a diagnostic scan tool, retrieve all  CMDTCs.

    Is DTC U0100:87 set in other modules? 

    Yes  GO to  C6
    No  GO to  C7

  8. C6 CHECK FOR CORRECT PCM (POWERTRAIN CONTROL MODULE) OPERATION

    • Ignition OFF.

    • Disconnect and inspect all PCM 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 all PCM 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, 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, Refer to PCM Guided Routine Testing .
    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.

  9. C7 CHECK FOR CORRECT BCM (BODY CONTROL MODULE) OPERATION

    • Disconnect and inspect all BCM 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 all BCM 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, 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, Refer to BCM Guided Routine .
    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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