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Home >> Ford >> 2024 >> F-150 Lightning Flash >> Repair and Diagnosis >> External Pages >> Different car >> Section 1576 (Exterior Lighting (Pinpoint Tests - Headlamps - Parking Lamps)) >> Diagnosis And Testing >> Headlamps - Vehicles With: Adaptive LED Headlamps >> Pinpoint Tests >> Pinpoint Test J: U0121:87 >> Pinpoint Test J: U0121:87

Pinpoint Test J: U0121:87

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  1. Normal Operation and Fault Conditions 

    REFER to: Exterior Lighting - System Operation and Component Description .

    DTC Fault Trigger Conditions 

    DTC Description Fault Trigger Condition
    HCM U0121:87 Lost Communication With Anti-Lock Brake System (ABS) Control Module 'A': Missing Message A continuous memory and on-demand DTC that sets in continuous memory if the HCM does not receive data messages from the ABS module through the GWM are missing for 5 seconds or longer.

    Possible Causes 

    • Communication concern
    • Battery voltage concern
    • ABS module
    • HCM

  2. J1 VERIFY THE CUSTOMER CONCERN

    • Ignition ON.

    • Verify there is an observable symptom present.

    Is an observable symptom present? 

    Yes  GO to  J2
    No  The system is operating normally at this time. The DTC may have been set due to high network traffic or an intermittent fault condition.

  3. J2 CHECK THE COMMUNICATION NETWORK

    • Using a diagnostic scan tool, perform the network test.

    Does the ABS module pass the network test? 

    Yes  GO to  J3
    No  REFER to: CONTROLLER AREA NETWORK (CAN) MODULE COMMUNICATIONS NETWORK (DESCRIPTION & OPERATION)

  4. J3 PERFORM THE ABS (ANTI-LOCK BRAKE SYSTEM) MODULE SELF-TEST

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

    Are any Diagnostic Trouble Codes (DTCs) recorded? 

    Yes  REFER to the appropriate DTC Chart (All-Inclusive)
    No  GO to  J4

  5. J4 RECHECK THE HCM (HEADLAMP CONTROL MODULE) DIAGNOSTIC TROUBLE CODES (DTCS)

    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.

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

    • Wait 10 seconds.

    • Repeat the HCM self-test.

    Is DTC U0121:87 still present? 

    Yes  GO to  J5
    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.

  6. J5 CHECK FOR DTC (DIAGNOSTIC TROUBLE CODE) U0121:87 SET IN OTHER MODULES

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

    • Ignition OFF.

    • Ignition ON.

    • Wait 10 seconds.

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

    • Retrieve the Continuous Memory Diagnostic Trouble Codes (CMDTCs) from all modules.

    Is DTC U0121:87 set in the BCM ' 

    Yes  GO to  J6
    No  GO to  J7

  7. J6 CHECK FOR CORRECT ABS (ANTI-LOCK BRAKE SYSTEM) MODULE OPERATION

    • Disconnect and inspect all ABS module and all related in-line 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 ABS module and all related in-line 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, INSTALL a new ABS module. REFER to: Anti-Lock Brake System (ABS) and Stability Control .
    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.

  8. J7 CHECK FOR CORRECT HCM (HEADLAMP CONTROL MODULE) OPERATION

    • Disconnect and inspect all HCM and all related in-line 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 HCM and all related in-line 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, INSTALL a new HCM. REFER to: Headlamp Control Module (HCM) .
    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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