The computers in your car constantly spit out useful data, and you can make sense of it with this OBD2 scanner from Foxwell, which is 15% off today when you clip the on-page coupon.
At $37, it’s a bit more expensive than the basic scanners that only tell you error codes, but it’s not that much more expensive considering all the extra features included. The color screen helps you make sense of all the data, it’ll let you know if you’ll pass your emissions test, and it can even display a live graph of various measures of engine performance to help you diagnose issues.