LEMON Manuals: Even more car manuals for everyone
Home >> Ford >> 2021 >> Mustang GT, Automatic Trans >> Repair and Diagnosis >> Electrical >> Gauges >> Instrumentation, Message Center And Warning Chimes (2 Of 2) >> Diagnosis And Testing >> Instrumentation, Message Center and Warning Chimes >> Pinpoint Tests >> Pinpoint Test CB: U0121:00

Pinpoint Test CB: U0121:00

  1. Normal Operation and Fault Conditions 

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

    DTC Fault Trigger Conditions 

    DTC Description Fault Trigger Condition
    IPC U0121:00 Lost Communication With Anti-Lock Brake System (ABS) Control Module "A": No Sub Type Information Sets in continuous memory in the IPC if data messages received from the ABS module through the GWM are missing for 5 seconds or longer.

    Possible Sources 

    • Communication concern
    • GWM concern
    • ABS module
    • IPC

  2. CB1 VERIFY THE CUSTOMER CONCERN

    • Ignition ON.

    • Verify there is an observable symptom present.

    Is an observable symptom present? 

    Yes  GO to  CB2
    No  Clear the DTC. 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. CB2 CHECK THE COMMUNICATION NETWORK

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

    Does the ABS module pass the network test? 

    Yes  GO to  CB3
    No  REFER to: Communications Network

  4. CB3 PERFORM THE IPC (INSTRUMENT PANEL CLUSTER) SELF-TEST

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

    Are any non-network Diagnostic Trouble Codes (DTCs) present? 

    Yes  REFER to DTC Chart: Instrument Panel Cluster (IPC) .
    No  GO to  CB4

  5. CB4 CHECK THE GWM (GATEWAY MODULE A) DIAGNOSTIC TROUBLE CODES (DTCS)

    • Using a diagnostic scan tool, check the GWM Continuous Memory Diagnostic Trouble Codes (CMDTCs).

    Are any Diagnostic Trouble Codes (DTCs) recorded? 

    Yes  REFER to: Communications Network
    No  GO to  CB5

  6. CB5 PERFORM THE ABS (ANTI-LOCK BRAKE SYSTEM) MODULE SELF-TEST

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

    Are any non-network Diagnostic Trouble Codes (DTCs) present? 

    Yes  REFER to: Anti-Lock Brake System (ABS) and Stability Control
    No  GO to  CB6

  7. CB6 RECHECK THE IPC (INSTRUMENT PANEL CLUSTER) DIAGNOSTIC TROUBLE CODES (DTCS)

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

    • Ignition OFF.

    • Ignition ON.

    • Wait 10 seconds.

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

    • Check the IPC Diagnostic Trouble Codes (DTCs).

    Is DTC U0121:00 still present? 

    Yes  GO to  CB7
    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.

  8. CB7 CHECK FOR OTHER CAUSES OF COMMUNICATION NETWORK CONCERN

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

    • CHECK the vehicle service history for recent service actions related to the ABS module, GWM or IPC. If recent service history is found:

      • verify correct replacement module was installed

        • HVBOM may be used to verify correct part fitment

      • verify the configuration of replacement module was correct

        • re-configure module using as-built data if prior configuration is suspect

      • verify the module was not obtained from a like vehicle and installed into customer vehicle

        • return the swapped module to source vehicle and obtain new replacement module

    • Operate the system and determine if the observable symptom is still present.

    Is the observable symptom still present? 

    Yes  GO to  CB8
    No  The system is operating correctly at this time. The concern may have been due to incorrect parts replacement procedures or incorrect module configuration.

  9. CB8 CHECK FOR CORRECT ABS (ANTI-LOCK BRAKE SYSTEM) MODULE OPERATION

    • Ignition OFF.

    • Disconnect and inspect all ABS module 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 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) Module
    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.
scientia non olet · About LEMON Manuals