Code Definition

U0556 (68) — Invalid Data Received From Front Display Interface Module (FDIM)

System: Network Communication  |  Type: Generic (OBD-II Standard)  |  Make: Generic

About U0556

U0556 is a generic (obd-ii standard) network communication diagnostic trouble code. It belongs to the U-prefix family of codes, which covers inter-module network communication (CAN, LIN, FlexRay, or similar) faults.

Scanning & clearing: Network (U) codes report communication faults between modules. When diagnosing U-codes, checking the vehicle's CAN bus integrity, supply/ground at each module, and reading all modules for related faults is usually the first step.

Because U0556 is a generic OBD-II code, its base definition is shared across manufacturers. The specific diagnostic steps, reference values, and repair procedures can vary by vehicle, and the TaT Diagnostic Assistant includes verified procedures submitted by working technicians.

Code Information

The Body Control Module and other networked modules communicate with the Front Display Interface Module over the CAN bus to exchange display status, warning messages, and driver information data. DTC U0556 sets when the receiving module detects that a valid CAN message from the FDIM is present but the data content is invalid, implausible, incorrectly formatted, or outside the expected parameter range. A failure type of 68 reflects a data plausibility or integrity fault rather than a total loss of communication. This is usually caused by FDIM software corruption, incorrect configuration, an uns...

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