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Home >> Ford >> 2023 >> Escape Base, 4WD >> Repair and Diagnosis >> External Pages >> Different car >> Section 1127 (Electric Powertrain Control - 3.3L DURATEC-V6 - Hybrid (BP) (Diagnosis & Testing - Removal & Installation)) >> Diagnosis And Testing >> Electric Powertrain Control >> Pinpoint Tests >> Pinpoint Test Aw: U0121

Pinpoint Test Aw: U0121

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  1. Normal Operation and Fault Conditions 

    Refer to Electric Powertrain Control - System Operation and Component Description .

    DTC Fault Trigger Conditions 

    DTC Description Fault Trigger Condition
    SOBDMC U0121:00 Lost Communication With Anti-Lock Brake System (ABS) Control Module "A": No Sub Type Information This DTC sets when messages are missing from the ABS module.

    Possible Sources 

    • Communications network concern
    • ABS module

  2. AW1 CARRY OUT A VEHICLE INSPECTION AND VERIFY THE SELF-TEST PROCEDURE

    NOTE: If the self-test or communication concern occurred after a failed or aborted reprogram, the module may be blank. Attempt to reprogram the module again before continuing with this pinpoint test.

    • Visually inspect the following for obvious signs of electrical damage:

      • harness wiring
      • electrical connections

    • Verify the correct procedure was used to activate the self-test for the scan tool. Refer to Diagnostic Methods .

    Was the correct self-test procedure used? 

    Yes  GO to  AW2
    No  Refer to Diagnostic Methods .

  3. AW2 CARRY OUT THE NETWORK TEST

      NOTE: When using FDRS, the scan tool attempts to communicate with the PCM first. After establishing communication with the PCM, the scan tool then attempts to communicate with all modules on the vehicle. If an FDRS session cannot be established, FDRS may state no communication can be established with the PCM:

      • Choose No when the scan tool prompts whether or not to retry communication.
      • Enter a PCM part number, tear tag or calibration number to identify the vehicle and start a session. The PCM part number and 4- character tear tag are located on the PCM.

    • Ignition ON.

    Do all modules indicate pass? 

    Yes  GO to  AW3
    No  GO to  AW4

  4. AW3 CHECK FOR AN ABS (ANTI-LOCK BRAKE SYSTEM) CONCERN

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

    • Check for any other ABS related symptoms.

    Is a concern present? 

    Yes  DIAGNOSE the ABS concern 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.

  5. AW4 INVERTER SYSTEM CONTROLLER (ISC) SELF-TEST

    • Confirm the Inverter System Controller (ISC) was the only module to fail.

    Was the Inverter System Controller (ISC) the only module to fail? 

    Yes  GO to  AW5
    No  DIAGNOSE the network concern. Refer to Communications Network .

  6. AW5 CHECK THE INVERTER SYSTEM CONTROLLER (ISC) B+ CIRCUIT FOR VOLTAGE

    • Ignition OFF.

    • Disconnect Inverter System Controller (ISC) C1458A .

    • Ignition ON.

    • Measure and record:
      Positive Lead Measurement / Action Negative Lead
      C1458A-M1
      GFD659138Courtesy of FORD MOTOR COMPANY
      		 Ground

    Is the voltage greater than 10.5 volts? 

    Yes  GO to  AW6
    No  REPAIR the circuit.

  7. AW6 CHECK THE INVERTER SYSTEM CONTROLLER (ISC) VPWR CIRCUITS FOR VOLTAGE

    • Ignition OFF.

    • Connect a 5A fused jumper between:
      Positive Lead Measurement / Action Negative Lead
      C1458A-K3
      GFD659139Courtesy of FORD MOTOR COMPANY
      		 Ground

    • Ignition ON.

    • Measure and record:
      Positive Lead Measurement / Action Negative Lead
      C1458A-L2
      GFD659138Courtesy of FORD MOTOR COMPANY
      		 Ground
      C1458A-M2
      GFD659138Courtesy of FORD MOTOR COMPANY
      		 Ground

    Are the voltages greater than 10.5 volts? 

    Yes  GO to  AW7
    No  REPAIR the circuit.

  8. AW7 CHECK THE INVERTER SYSTEM CONTROLLER (ISC) GROUND CIRCUITS FOR AN OPEN

    • Ignition OFF.

    • Measure and record:
      Positive Lead Measurement / Action Negative Lead
      C1458A-L4
      GFD659137Courtesy of FORD MOTOR COMPANY
      		 Ground
      C1458A-M4
      GFD659137Courtesy of FORD MOTOR COMPANY
      		 Ground

    Are the resistances less than 5 ohms? 

    Yes  DIAGNOSE the network concern. Refer to Communications Network .
    No  REPAIR the open circuit.
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