Code Definition

U1121 — CAN bus data TCM communication data corrupt

System: Network Communication  |  Type: Manufacturer-Specific  |  Make: Mitsubishi

About U1121

U1121 is a manufacturer-specific network communication diagnostic trouble code recorded for Mitsubishi 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.

U1121 is a manufacturer-specific code. The same code string on a different make may have a different meaning. Always confirm the code's definition against the vehicle's service information for the specific make and model under test.

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