DTC U0420: Invalid Data Received From Power Steering Control Module: Action
WARNING: This page does not describe the selected car, but rather 27 other vehicles, including the 2022 Lincoln Navigator, 2022 Lincoln Nautilus, 2022 Lincoln Corsair, 2022 Lincoln Aviator, and 2022 Ford Transit-350 HD. However, it is still accessible from the selected car via links, so may be relevant.
This DTC sets if the SECM receives invalid data from the EPAS status message. Using a diagnostic scan tool, RETRIEVE and DIAGNOSE all PSCM DTCs. REFER to the the Power Steering article. If the diagnostic scan tool cannot communicate with the PSCM, REFER to Module Communications Network article. If no DTCs are set in the PSCM, the concern may be intermittent. SET the ignition to OFF. DISCONNECT and INSPECT all PSCM electrical connectors and related inline connectors for corrosion, bent pins, pushed-out pins and spread terminals. REPAIR as necessary.