2002 Mercedes-Benz C-Class "speed p2203" Questions

...he could not solve the problems. He has been trying trial and error method i.e experimenting on my car at my expenses. p0500 code is ecm/speed sensor faulty or wirening/p2203 is particulate trap bank ...

...P2203 on ml 270 cdi 04/2000 Component Y3/6N3 speed sensor 3 is faulty,That is a transmission code...the trans speed sensors are MADE into a printed circuit board that connects to the valve body...MB ...