About OBDIICSU

OBDIICSU is a free reference for OBD-II diagnostic trouble codes (DTCs). Our goal is simple: when your scan tool reports a code, you should be able to look it up and quickly understand what it means, why it happens and what to check first.

The database currently covers 3,395 codes across the four standard OBD-II families \u2014 Powertrain (P), Body (B), Chassis (C) and Network (U). Each code page explains the code’s meaning, when it is set, common symptoms, possible causes, and a practical first-checks list, along with related codes.

How our information is compiled

Code definitions follow the standardized SAE J2012 structure used across the industry. Generic codes (those with a 0 as the second character) share the same core meaning across manufacturers; manufacturer-specific codes can vary, and we note this on each page. The symptoms, causes and checks we list reflect common diagnostic practice for each system.

Important limitation

This site is an informational reference, not a repair manual and not professional advice. Always confirm a diagnosis with a scan tool, and consult a qualified technician before replacing parts. See our Privacy Policy for how the site handles data and advertising.