Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
DTC U0420: Invalid Data Received From Power Steering Control Module: Action
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 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 in-line connectors for corrosion, bent pins, pushed-out pins and spread terminals. REPAIR as necessary.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- β’ You smell fuel, burning insulation, or see smoke.
- β’ Brakes feel soft, pull hard to one side, or make grinding noises.
- β’ The engine overheats, stalls repeatedly, or misfires under load.
- β’ You are missing required tools, torque specs, or safe lifting equipment.
- β’ You are not confident in the next step or safety outcome.