Code Definition

U0402 (61) — Invalid Data Received From Transmission Control Module (TCM)

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

About U0402

U0402 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 U0402 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 operating data. DTC U0402 sets when one or more modules receive CAN messages from the Transmission Control Module that are outside expected parameters or contain invalid values. A failure type byte of 61 indicates the received data is implausible or inconsistent with operating conditions rather than missing, so the TCM is communicating but the content is wrong. This is typically logged when the TCM transmits corrupted or incorrect data due to internal faults, an unstable power or ground supply, or CAN in...

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