Code Definition

U0001 — High speed CAN communication bus

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

About U0001

U0001 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 U0001 is stored, the module has detected a signal or supply voltage higher than the expected operating range.

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 U0001 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 U0001 indicates a fault on the high-speed Controller Area Network (CAN) communication bus, which is the primary 500 kbps digital network linking the vehicle's core control modules including the ECM/PCM, TCM, ABS module, SRS module, BCM, instrument cluster, power steering module, and gateway. The high-speed CAN bus uses a twisted pair of wires (CAN-H and CAN-L) with 120-ohm termination resistors at each end of the bus, resulting in a nominal termination resistance of approximately 60 ohms measured across the bus. This code is set when a control module detects that the high-speed CAN bus has...

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