Code Definition

U0557 (81-08) — Invalid Data Received From Front Controls Interface Module A

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

About U0557

U0557 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 U0557 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 Front Controls Interface Module A over the CAN bus to receive switch status and control input data for climate, audio, and comfort functions. DTC U0557 sets when the receiving module detects that a valid CAN message from the controls interface module is present but the data content is invalid, implausible, incorrectly formatted, or inconsistent with expected operating states. A failure type of 81 with an 08 qualifier reflects a data integrity or internal processing fault rather than a complete loss of communication. This is u...

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