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Pinpoint Test W: DTC (Diagnostic Trouble Code) U0401:86

WARNING: This page is about a different car, the 2023 Ford Bronco. However, it is still accessible from the selected car via links, so may be relevant.
  1. Normal Operation and Fault Conditions 

    REFER to: Lane Keeping System - System Operation and Component Description .

    DTC Fault Trigger Conditions 

    DTC Description Fault Trigger Condition
    IPMA U0401:86 Invalid Data Received from ECM/PCM A: Signal Invalid This continuous memory DTC can set in the IPMA due to a fault in the PCM or an input to the PCM.

    Possible Sources 

    • PCM concern

  2. W1 CHECK FOR PCM (POWERTRAIN CONTROL MODULE) SIGNAL

    • Ignition ON.

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

    Is DTC U0401:86 still present? 

    Yes  RETRIEVE and FOLLOW non-network Diagnostic Trouble Codes (DTCs) from the PCM REFER to: Electronic Engine Controls - 2.3L EcoBoost (199kW/270PS), . REFER to: Electronic Engine Controls - 2.7L EcoBoost (238kW/324PS),
    (303-14B Electronic Engine Controls - 2.7L EcoBoost (238kW/324PS), Diagnosis and Testing)..
    No  DIAGNOSE the observable symptom.