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Pinpoint Test Bi: PSCM (Power Steering Control Module) DTC (Diagnostic Trouble Code) U0256:00 Lost Communication With Front Controls Interface Module

  1. NOTE: Refer to Steering GSB for additional connector and wiring inspection tips.

    Refer to Power Steering Controls for schematic and connector information.

    Normal Operation and Fault Conditions 

    Description 

    • Description 
    • The PSCM monitors the HS-CAN messages when the ignition has been on for more than 5 seconds, the voltage to the PSCM is greater than 10 volts and there are no Diagnostic Trouble Codes (DTCs) present inhibiting PSCM operation.
    • For additional information on the messages sent to the PSCM from the FCIM, REFER to: Power Steering - System Operation and Component Description .

    Pinpoint Test Applicability 

    • Pinpoint Test Applicability 
    • This test applies to PSCMDTC U0256 Lost Communication with the FCIM only. It does not apply to any other module except the PSCM.

    DTC Diagnostic Strategy 

    • DTC Diagnostic Strategy 
    • If the module DTC list results in a large number of Diagnostic Trouble Codes (DTCs), diagnose all module hard faults first (C102D, C1B00, C200B, C200C, C200D, U2011 and U3000) before diagnosing any network faults (lost communication or invalid data). If voltage concern Diagnostic Trouble Codes (DTCs) are present, diagnose those after any module hard faults and before any network faults. Diagnose all current and active Diagnostic Trouble Codes (DTCs) before diagnosing any historic Diagnostic Trouble Codes (DTCs).

    Pinpoint Test Purpose 

    • Pinpoint Test Purpose 
    • To verify the PSCM wiring harness and connectors are OK. This test checks the connectors and wiring from the PSCM 3 pin connector at the steering gear to the in-line connector in the engine compartment. If these circuits are working correctly, the test then directs to check the FCIM and wiring harness.

    Diagnostic Aids 

    • Diagnostic Aids 
    • Do not install a new PSCM as part of the repair for a PSCMDTC U0256:00.
    • DTC U0256:00 indicates a possible failure of the HS-CAN which can be due to a circuit fault in the HS-CAN, the PSCM wiring harness or a FCIM concern.

    DTC Fault Trigger Conditions 

    DTC Description Fault Trigger Condition
    PSCM U0256:00 Lost Communication With Front Controls Interface Module 'A': No Sub Type Information This DTC sets when the PSCM does not receive the FCIM messages within a certain time frame. This can occur if the FCIM wiring harness or electrical connectors are loose or damaged, or if the vehicle battery state of charge levels are low.

    Possible Causes 

    • Fuse(s)
    • Wiring, terminals or connectors
    • Network communication concern
    • FCIM

  2. BI1 VERIFY PSCM (POWER STEERING CONTROL MODULE) DTC (DIAGNOSTIC TROUBLE CODE)

    • Ignition ON.

    • Clear the PSCMDTC s.

    • Ignition OFF.

    • Ignition ON.

    • Carry out the PSCM self-test.

    Is DTC U0256:00 currently present and active in the PSCM ' 

    Yes  GO to  BI2
    No  If the PSCM does NOT list DTC U0256 Lost Communication With The FCIM, DISCONTINUE this test and REFER to the DTC Chart for diagnostic direction.

  3. BI2 CHECK THE VEHICLE BATTERY AND CHARGING SYSTEM VOLTAGE

    • Ignition ON.

    • REFER to: Battery and carry out Pinpoint Test A: Battery Condition Test (battery state of charge).

    Did the battery pass the condition test (battery state of charge)? 

    Yes  GO to  BI3
    No  INSTALL a new 12-volt battery. REFER to: Battery . GO to  BI3

  4. BI3 INSPECT THE PSCM (POWER STEERING CONTROL MODULE) COMMUNICATION WIRING AND CONNECTORS

    • Ignition OFF.

    • Inspect all disconnected connectors for:

      • Pushed-out pins, loose pins, bent pins, spread terminals, water ingress and corrosion.
      • Missing or loose latches, broken or cracked connector housings.
      • VDB wiring for pinched or cut wiring under brackets, air cleaner boxes, battery trays, engine pulleys, etc.

    • Inspect the VDB wiring for pinched or cut wiring under brackets, air cleaner boxes, battery trays, engine pulleys, etc.

    • Inspect the VDB wiring harness anchors for coming loose from anchoring locations in the engine compartment.

    • Repair the connectors or wiring as necessary.

    • Ignition ON.

    • Clear the PSCMDTC s.

    • Ignition OFF.

    • Ignition ON.

    • Carry out the PSCM self-test.

    Is DTC U0256:00 currently present and active in the PSCM ' 

    Yes  GO to  BI4
    No  The concern is not present at this time and may have been set due to a loose or damaged electrical connector. The test is complete, no further action is required.

  5. BI4 CHECK THE HS-CAN (HIGH-SPEED CONTROLLER AREA NETWORK) CIRCUITS FOR AN OPEN

    • Ignition OFF.

    • Disconnect GWM connector, C2431.

    • Disconnect PSCM _A connector, C1463B.

    • Measure the resistance between:
      Positive Lead Measurement / Action Negative Lead
      C1463B Pin 2
      GFD858238Courtesy of FORD MOTOR COMPANY
      		 C2431 Pin 18
      C1463B Pin 3
      GFD858238Courtesy of FORD MOTOR COMPANY
      		 C2431 Pin 17

    Are the resistances less than 3 ohms? 

    Yes  The HS-CAN circuits are OK, GO to  BI5
    No  REPAIR the circuit.

  6. BI5 RECHECK FOR PSCM (POWER STEERING CONTROL MODULE) DTC (DIAGNOSTIC TROUBLE CODE) U0256:XX

    • Connect PSCM _A connector, C1463B. Make sure the connector seats and latches correctly.

    • Connect GWM connector, C2431. Make sure the connector seats and latches correctly.

    • Ignition ON.

    • Clear the PSCMDTC s.

    • Ignition OFF.

    • Ignition ON.

    • Carry out the PSCM self-test.

    Is DTC U0256:00 currently present and active in the PSCM ' 

    Yes  The PSCMHS-CAN circuits are working correctly at this time. RETRIEVE and RECORD all FCIMDTCs. REFER to: Information and Entertainment System .
    DIAGNOSE the FCIM.
    No  If the PSCM no longer lists DTC U0253::xx, the concern was repaired during this pinpoint test and the PSCMHS-CAN circuits are working correctly at this time.
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