Code Definition

U0002 — High speed CAN communication bus Circuit performance

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

About U0002

U0002 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.

When U0002 is stored, the module has detected a signal or supply voltage higher than the expected operating range; and a plausibility fault — the measured value is in the electrical range but is not consistent with expected operating behaviour.

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 U0002 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

DTC U0002 is a generic network communication code indicating that the high speed CAN (Controller Area Network) bus is operational but exhibiting degraded performance. Unlike U0001 which indicates a complete bus failure, U0002 is set when a control module detects that the high speed CAN bus is communicating but with excessive error rates, intermittent signal quality issues, or data integrity problems that fall outside acceptable parameters. The high speed CAN bus operates at 500 kbps and connects critical powertrain, chassis, and body control modules. Circuit performance issues typically manife...

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