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Pinpoint Test AO: PSCM (Power Steering Control Module) DTC (Diagnostic Trouble Code) U0159:00 Lost Communication With Parking Assist Control Module "A"

WARNING: This page is about a different car, the 2024 Ford Maverick. However, it is still accessible from the selected car via links, so may be relevant.
  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 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 PAM module, REFER to: Power Steering - System Operation and Component Description 

    Pinpoint Test Applicability 

    • Pinpoint Test Applicability 
    • This test applies to PSCM DTC U0159 Lost Communication with the PAM 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 PAM and wiring harness.

    Diagnostic Aids 

    • Diagnostic Aids 
    • Do not install a new PSCM as part of the repair for a PSCM DTC U159:00.
    • DTC U0159:00 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 PAM concern.
    • The presence of DTC U0159:00 prevents the active park assist system (if equipped) from activating. If set during an active park assist event, the event is terminated and the active park assist system is deactivated.

    DTC Fault Trigger Conditions 

    DTC Description Fault Trigger Condition
    PSCM U0159:00 Lost Communication With Parking Assist Control Module 'A': No Sub Type Information This DTC sets when the PSCM does not receive the PAM module messages within a certain time frame. This can occur if the PAM module 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
    • PAM

    NOTE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may cause damage to the connector.

  2. AO1 VERIFY PSCM (POWER STEERING CONTROL MODULE) DTC (DIAGNOSTIC TROUBLE CODE)

    • Ignition ON.

    • Clear the PSCM DTC s.

    • Ignition OFF.

    • Ignition ON.

    • Carry out the PSCM self-test.

    Is DTC U0159:00 currently present and active in the PSCM ' 

    Yes  GO to  AO2
    No  If the PSCM does NOT list DTC U0159 Lost Communication With The PAM, DISCONTINUE this test and REFER to the Diagnostic Trouble Code (DTC) Chart  for diagnostic direction.

  3. AO2 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  AO3
    No  INSTALL a new 12-volt battery. REFER to: Battery GO to  AO3

  4. AO3 INSPECT THE PSCM (POWER STEERING CONTROL MODULE) COMMUNICATION WIRING AND CONNECTORS

    NOTE: The PSCM receives messages from other modules through 2 connectors: the PSCM -A (or B) 3-pin connector at the gear and the multi-pin in-line connector in the engine compartment. The in-line connector receives messages from the other modules into the PSCM wiring harness. The PSCM wiring harness uses the VDB wiring to carry the messages from the in-line connector to the PSCM -A (or B) 3-pin connector. If any of the connector pins or VDB communication wires are loose or damaged, the PSCM cannot properly receive messages from other modules.

    • 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 PSCM DTC s.

    • Ignition OFF.

    • Ignition ON.

    • Carry out the PSCM self-test.

    Is DTC U0159:00 currently present and active in the PSCM ' 

    Yes  GO to  AO4
    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. AO4 CHECK THE HS-CAN (HIGH-SPEED CONTROLLER AREA NETWORK) CIRCUITS FOR AN OPEN

    • Ignition OFF.

    • Disconnect GWM connector, C2431.

    • Disconnect PSCM _A connector, C225A.

    Are the resistances less than 3 ohms? 

    Yes  The HS-CAN circuits are OK, GO to  AO5
    No  REPAIR the circuit.

  6. AO5 RECHECK FOR PSCM (POWER STEERING CONTROL MODULE) DTC (DIAGNOSTIC TROUBLE CODE) U0159:XX

    • Connect PSCM _A connector, C225A. Make sure the connector seats and latches correctly.

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

    • Ignition ON.

    • Clear the PSCM DTC s.

    • Ignition OFF.

    • Ignition ON.

    • Carry out the PSCM self-test.

    Is DTC U0159:00 currently present and active in the PSCM ' 

    Yes  The PSCMHS-CAN circuits are working correctly at this time. RETRIEVE and RECORD all PAM DTC s. REFER to: Parking Aid
    DIAGNOSE the PAM.
    No  If the PSCM no longer lists DTC U0159::xx, the concern was repaired during this pinpoint test and the PSCMHS-CAN circuits are working correctly at this time.
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