Hi all.. I just repaired my 98 C230 yesterday by having the codes read last month and getting a P0170 and other codes reffering to multiple misfires. (due to a bad Mass Air Flow sensor.)
I replaced the MAS and the car runs like new again. Although it was kind weird trying to drive the car as it "learned" the new MAS.
No codes but noone will reset the OBDII for me. The say its illegal, because they didn't do the repair. I showed them the receipts for the parts, but no go.

So.. other than disconnecting the battery, (I don't have the stereo codes for this one) How can I reset the Check Engine Light myself.
Pull a fuse? Jump terminals in the 36 pin connector??

 

It's not illegal to reset a check engine light on a car. A lot of the local auto parts stores will do it for no charge with their own OBDII scanner. I know they will here because they do it all the time for people who don't completely close their gas cap properly throwing a code. Once tightened and run for a bit, they are happy to reset the check engine light. Ridiculous. For not too much money, you can go on amazon and buy your own OBDII that will read AND reset codes which is what I did. Simple. Then you'll have the tool and won't have to rely on people holding you hostage over something as simple as a light on the dash.