DTC U0401: Invalid Data Received from ECM/PCM A: Action

CARRY OUT a self-test of the PCM. If the diagnostic scan tool indicates the module is not responding, REFER to MODULE COMMUNICATIONS NETWORK (EXCEPT HYBRID/ENERGI) to diagnose the network communication concern. If PCM DTCs are present, REFER to ENGINE CONTROLS - INTRODUCTION (EXCEPT DIESEL & HYBRID) to diagnose the PCM system fault. If there are no DTCs in the PCM, SET the ignition to OFF. DISCONNECT and INSPECT all PCM electrical connectors and related in-line connectors for corrosion, bent pins, pushed-out pins and spread terminals. REPAIR as necessary.