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 U0401: Invalid Data Received from ECM/PCM A: 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 9 volts and there are no DTCs present inhibiting PSCM operation.
The PCM uses input from several sensors and components to gather vehicle data, then sends this data to the PSCM. If the data is corrupted or invalid, the PCM sends out "invalid", "fault" or "unknown" instead of the actual data. For a list of the messages sent to the PSCM from the PCM, refer to the Network Message List in Description and Operation in the Power Steering article.
- DTC U0401:00 (Invalid Data Received from ECM/PCM A) - This DTC is set if the PSCM receives invalid or unknown messages from the PCM instead of the actual engine speed (non-hybrid), ready light (hybrid) and vehicle speed (all) data messages, and DTC U0001:00 is not present in the PSCM.
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.