What does code U0090 mean?

Q: What does code U0090 mean?

Vehicle Communication Bus G (-) High. U0090 is a generic network communication code indicating that the vehicle's communication bus G negative circuit is reading a high voltage condition, which means the controller area network (CAN) data line is stuck at or near battery voltage instead of toggling normally. The computer that monitors this bus detected an abnormal high signal on the G (-) line, which can prevent modules from exchanging data and may cause multiple systems to set communication codes.

DTC codes / U00xx · Network wiring and bus faults / U0090

U0090Vehicle Communication Bus G (-) High

U0090 is a generic network communication code indicating that the vehicle's communication bus G negative circuit is reading a high voltage condition, which means the controller area network (CAN) data line is stuck at or near battery voltage instead of toggling normally. The computer that monitors this bus detected an abnormal high signal on the G (-) line, which can prevent modules from exchanging data and may cause multiple systems to set communication codes.

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.