U00011 min
U0001: High Speed CAN Bus Error Fix Guide
U0001: High Speed CAN Bus Error Fix Guide. See symptoms, common causes, driving risk and checks that help confirm the fault before parts are replaced.
Read diagnostic guide →Diagnostic system
CAN Bus and Module Communication Codes
Trace lost-communication, invalid-data and bus-off faults by checking battery state, module power, grounds and network behavior in a logical order.
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A missing module may not have a network fault
A controller that has lost power or ground cannot communicate. Start with a complete vehicle scan, note which modules respond, and check battery condition before measuring the bus.
Avoid creating a second fault
Do not pierce twisted-pair wiring or connect a meter carelessly. Network topology, terminating resistance and wake-up behavior vary, so follow the correct vehicle diagram and test location.