OBD fault code library
Look up any P or U code to see what it means, what causes it, the parts involved and how it gets fixed.
Free on OBD DashX
Looking for real-world repair data?
OBD DashX shows which problems come with each code, how often they show up in other vehicles, and how to fix them — step by step.
- Real-world fix data
- How often it happens
- Step-by-step repairs
Fault codes
U0009
High Speed CAN Communication Bus (-) shorted to Bus (+)
Communication Network System
High severity
Scan your own car
Read and clear fault codes, live data and service resets with the CaRPM app.