Code Definition

U0418 (68-AF) — Data Invalid From Braking System Control Module A

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

About U0418

U0418 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 U0418 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 vehicle control modules communicate over the Controller Area Network (CAN) to exchange braking and stability control data. DTC U0418 sets when one or more modules receive CAN messages from Braking System Control Module A that are outside expected ranges or logically inconsistent. A failure type byte of 68 indicates a data plausibility or range error, while an AF qualifier denotes the received data is invalid or corrupt. This is typically logged due to internal module faults, an unstable power or ground supply, or CAN integrity issues affecting the braking module. Because this module contro...

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