An illuminated Check Engine Light is an automatic smog check failure. Be cautious. A smog test station is not required to refuse the inspection of your Mercedes Benz C220 simply because the Check Engine Light is on. The smog station will smog check your MBZ C220 and your vehicle will fail the smog inspection; you will still be required to pay for the smog test.
It is recommend you get a smog check diagnosis from a certified smog check repair station, and have your Mercedes' fault(s) repaired. The check engine light may then be reset and turn off.
