Code Definition

U0123 (00-8A) — Lost Communication With Yaw Rate Sensor

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

About U0123

U0123 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 U0123 is stored, the module has detected a sensor-related fault — the reported value from the named sensor is out of spec.

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 U0123 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 U0123 indicates lost communication with the Yaw Rate Sensor. The yaw rate sensor reports the vehicle rotation about its vertical axis to the stability control system, usually sending data over the CAN network or a dedicated link to the ABS and stability control module. The code sets when the receiving module stops receiving valid yaw rate messages within a calibrated time. Because stability control relies on this input, the system typically disables, and the driver sees the stability control, ABS, and traction warning lights with those functions inactive until communication is restored.

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