Hey Bazzle I have been surfing the site and thought you might be able to help me with this question... I work away from home, was gone for a couple of months, got home, had to charge the battery on our 99' slk 230 k, when I fired it up I had 5 obdII codes I cleared them all, (after writing them down) and the cel went away and has not returned... yet. Should I be concerned? Thanx