Free repair & diagnostic guides
Learn how to read your own codes, understand warning lights, and decide what to do next — written for drivers, DIYers, and first-time wrenchers.
How to check engine light codes
Use an OBD2 scanner to read the code and understand what it means — even if you've never done it before.
Can I drive with the check engine light on?
Steady vs flashing light: when it's safe to keep driving and when you should pull over immediately.
How to read your own codes
A simple Bluetooth adapter and a phone app can read the same codes a shop reads. Here's how.
What a scan tool tells you
Decode DTCs, live data, freeze-frame, and manufacturer codes to make sense of any warning light.
Want the full diagnosis for your car?
Look up a code or describe your symptom and get tailored repair help.