Code Definition

U0122 — Lost Communication with Vehicle Dynamic Control Module

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

About U0122

U0122 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 U0122 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

Control modules on the high speed CAN bus continuously exchange data with the Vehicle Dynamic Control (VDC/ESC) module to support stability control, traction control, and ABS braking functions. DTC U0122 is set when a receiving module does not receive valid CAN messages from the Vehicle Dynamic Control module within a calibrated time threshold while the rest of the network remains active. This usually means the VDC module is offline, unpowered, poorly grounded, or unable to communicate because of an open, short, or high resistance fault in its CAN connection. When this code is set the driver t...

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