Code Definition

U2106 — CAN Bus No Communication With Transmission Control Module

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

About U2106

U2106 is a generic (obd-ii standard) network communication diagnostic trouble code recorded for Holden vehicles. 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 U2106 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 exchange critical operating data with the Transmission Control Module (TCM) to coordinate gear selection, torque management, and shift strategy. DTC U2106 is set when a receiving module does not detect valid CAN messages from the TCM within a calibrated time period while the rest of the CAN network remains active. This indicates the TCM is offline because of loss of power or ground, an open, short, or high resistance fault in its CAN connection, or an internal TCM failure that prevents network participation. When this code is set the transmission commo...

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