Code Definition

U0073 — Control Module Communication Bus 'A' Off

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

About U0073

U0073 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 U0073 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 U0073 sets when a control module detects that communication bus A, typically the high speed CAN network, has gone to a bus off state and is no longer carrying data. A bus off condition occurs when a module accumulates too many transmission errors, which usually means the bus wiring is shorted or open, or a single module is corrupting the network. With the bus down, multiple modules lose the ability to share data, so a wide range of systems can be affected at once. When the code is set the driver may see several warning lamps, gauges that stop working, and features that rely on network data...

Join TaT to view the complete code information and diagnostic details.

Quick Facts