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
2018 Ford Expedition MAX Limited, 4WDSECTION DTC U0401: Invalid Data Received from ECM/PCM A
| Failure | Action |
|---|---|
| 00 | This DTC sets if the SASM receives invalid data in the gear lever position message or the power pack status message. RETRIEVE and DIAGNOSE all PCM and GWM DTCs. REFER to the Diagnosis and Testing in Module Communications Network article or the applicable Electronic Engine Controls article. If there are no DTCs in the PCM or GWM, the DTC may be caused by an intermittent concern. SET the ignition to OFF. DISCONNECT and INSPECT all PCM and GWM electrical connectors and related in-line connectors for corrosion, bent pins, pushed-out pins and spread terminals. REPAIR as necessary. |
| 81 | This DTC sets if the SASM receives invalid data in the vehicle speed quality factor check message. RETRIEVE and DIAGNOSE all PCM and GWM DTCs. REFER to the Diagnosis and Testing in Module Communications Network article or the applicable Electronic Engine Controls article. If there are no DTCs in the PCM or GWM, the DTC may be caused by an intermittent concern. SET the ignition to OFF. DISCONNECT and INSPECT all PCM and GWM electrical connectors and related in-line connectors for corrosion, bent pins, pushed-out pins and spread terminals. REPAIR as necessary. |
| 82 | This DTC sets if the SASM receives invalid data in the vehicle speed counter check message. RETRIEVE and DIAGNOSE all PCM and GWM DTCs. REFER to the Diagnosis and Testing in Module Communications Network article or the applicable Electronic Engine Controls article. If there are no DTCs in the PCM or GWM, the DTC may be caused by an intermittent concern. SET the ignition to OFF. DISCONNECT and INSPECT all PCM and GWM electrical connectors and related in-line connectors for corrosion, bent pins, pushed-out pins and spread terminals. REPAIR as necessary. |
| 83 | This DTC sets if the SASM receives invalid data in the vehicle speed checksum check message. RETRIEVE and DIAGNOSE all PCM and GWM DTCs. REFER to the Diagnosis and Testing in Module Communications Network article or the applicable Electronic Engine Controls article. If there are no DTCs in the PCM or GWM, the DTC may be caused by an intermittent concern. SET the ignition to OFF. DISCONNECT and INSPECT all PCM and GWM 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:
- • 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.