Code Definition

U0403 — Implausible Data Received From Transfer Case Module

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

About U0403

U0403 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 U0403 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 transfer case control module reports data such as range position, drive mode, and torque status to the Powertrain Control Module, the ABS and stability module, and other drivetrain controllers over the CAN data network. DTC U0403 is a generic network code set when a receiving module is still receiving messages from the transfer case module but the data they contain is implausible, out of range, or in conflict with other drivetrain inputs. Unlike a lost communication code, the bus link is working, so the problem lies in the value being sent, its source sensor, the module software, or a conf...

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