Scan tools

I bought the Zurich ZR-13 from HF last October while on the road and having the CEL come on. I haven't used it much, but it has some features that I wanted, like the ability to reset the oil change interval on my BMW. It didn't help much with the CEL problem except to clear the codes. It is an issue that will not show up except under certain weird conditions (quick restroom stop at 2,500 ft elevation or so). It is also a very uncommon code to have set.