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 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.