DTC U0556: Invalid Data Received From Front Display Interface Module: Action
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This DTC sets if the SECM receives invalid data from the FDIM. Using a diagnostic scan tool, RETRIEVE and DIAGNOSE all FDIM DTCs. REFER to the appropriate Information and Entertainment System article. If the diagnostic scan tool cannot communicate with the FDIM, REFER to appropriate Module Communications Network article. If no DTCs are set in the FDIM, the concern may be intermittent. SET the ignition to OFF. DISCONNECT and INSPECT all FDIM electrical connectors and related in-line connectors for corrosion, bent pins, pushed-out pins and spread terminals. REPAIR as necessary.