DTC U0404: Invalid Data Received from Gear Shift Control Module A: Signal Invalid: Action

This DTC sets if the GSM state message or the GSM button quality state is invalid or faulty. Using a diagnostic scan tool, RETRIEVE and DIAGNOSE all GSM DTCs. REFER to Diagnosis and Testing in the appropriate Automatic Transmission External Controls article. If no GSM DTCs are present, the DTC may be caused by an intermittent concern. SET the ignition to OFF. DISCONNECT and INSPECT all GSM module electrical connectors for corrosion, bent pins, pushed-out pins and spread terminals. REPAIR as necessary.