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
Browse codes on OBD DashX No sign-up needed · available in 10 languages
U21B2 /codes/dtcs/u21b2
Communication Network System
U21B3 /codes/dtcs/u21b3
Communication Network System
U21B4 /codes/dtcs/u21b4
Communication Network System
U21B5 /codes/dtcs/u21b5
Communication Network System
U21B6 /codes/dtcs/u21b6
Communication Network System
U21B7 /codes/dtcs/u21b7
Communication Network System
U21BA /codes/dtcs/u21ba
Communication Network System
U21BB /codes/dtcs/u21bb
Communication Network System
U21BC /codes/dtcs/u21bc
Communication Network System
U21BD /codes/dtcs/u21bd
Communication Network System
U21BE /codes/dtcs/u21be
Communication Network System
U21BF /codes/dtcs/u21bf
Communication Network System
U21C0 /codes/dtcs/u21c0
Communication Network System
U21C2 /codes/dtcs/u21c2
Communication Network System
U21C3 /codes/dtcs/u21c3
Communication Network System

Search fault codes

Scan your own car

Read and clear fault codes, live data and service resets with the CaRPM app.