Code Definition

U0204 — Lost Communication With Door Control Module

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

About U0204

U0204 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 U0204 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

The receiving control module (typically the body control module, central gateway, or instrument cluster depending on vehicle architecture) monitors CAN bus communication with the Door Control Module (DCM) to confirm regular message transmission and network integrity. The Door Control Module manages door related functions such as power window operation, central locking, side mirror control, courtesy lamp activation, and on premium vehicles ambient lighting, memory seat recall, and approach detection. DTC U0204 is set when expected data messages from the door control module are not received with...

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