OBD2 Code Lookup
Search 200+ OBD2 fault codes. Get plain-English explanations, symptoms, causes, and recommended scanner tools.
About OBD2 Codes
OBD2 (On-Board Diagnostics, 2nd generation) has been mandatory on all US vehicles since 1996. When something goes wrong, the vehicle's ECU stores a Diagnostic Trouble Code (DTC) that you can read with a scan tool.
Codes are structured as follows: the first letter indicates the system (P = Powertrain, B = Body, C = Chassis, U = Network). The second digit indicates manufacturer-specific (1) vs. generic (0). The remaining three digits identify the specific fault.
For the full repair procedure and wiring diagrams for any code, the individual code pages go much deeper than this lookup tool. And if you don't have a scanner yet, the OBD2 scanner comparison guide covers the best options for DIYers.