I have read the stuff on Error Code P-0243,

Looks like I should clean the "MAF" but I don't actually know what this stands for or where it is......any help appreciated on this, thanks.

btw, I bought a 'transducer' or solenoid from Phil for $122, problem not solved. I put the new transducer on the passenger side then used the old one from passenger side and installed it on the driver's side. There is a buzzing sound coming from both of these transducers after I shut the car off...it buzzes for maybe 10 minutes or so.

The turbo might be working now..honestly it's tough to tell I've been driving it like this for thousands of miles. A number of incompetent and dishonest mechanics including "Enrique" from Mr. MB Motors who quoted me $300+ for the part Phil sold me for $122. This guy came highly recommended by "posters"

MAF is short term for mass air flow sensor.
Found in inlet trunking ,it measures flow of air and air temperature into the engine.
It can be unplugged on most systems (ignition off) and the ecu will then run default settings.

The link below will guide you through cleaning and the location of it.
http://forums.mercedesclub.org.uk/showthread.php?t=18298

i had a MAF error and found one on eBay that I got for a total of $12 including shipping. The cheapest one I found new was $175 at *********.com.

I've owned the car since Jan, and replaced the MAF last weekend. It made an incredible difference in how the car performs.

thanks for that info, will try it