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DTC codes / U00xx · Network wiring and bus faults / U009D

U009DVehicle Communication Bus J

U009D is a generic network communication code indicating that the vehicle's control modules cannot reliably exchange data on the communication bus designated as 'J' by the manufacturer. The computer has detected a loss of expected messages, excessive bus errors, or a complete absence of traffic on that particular bus segment, which prevents modules from sharing information needed for normal operation.

SystemNetwork
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyProfessional
AreaNetwork wiring and bus faults

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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