Mercedes-Benz C230 Forum : “Check engine light topick from april 13”

yes

so what is?

Some auto parts stores will scan your computer for free. But with a Mercedes, there will be some codes they cannot retrieve. You'll have to go to a independant German mechanic ($) or  a Dealer. ($$$)
When you do, post the OBDII codes they give you on here. I can tell you what 90% of them mean.

I have a 2000 C230 with 93,000 and the engine light came on. Before going to a dealership try the following because it worked for me. I purchased Chevron Techron Fuel System Cleaner and put it in the gas tank when it was almost empty. I drove the car for about one week and the check engine light went off. The reason was the Fuel System cleaner works well to keep the gas clean and as a mechanic told me, it often takes 15 - 20 cycles (drives) before the engine light corrects itself. It took about 5 days for the problem to stop but hope this experience helps. Remember the common problem for the check engine light to show is a loose gas cap.