Filed Under (Mercedes-Benz) by admin on 25-05-2011
The Check Engine Light came ON on my C230 Kompressor Sport Coupe; the fault code was P0170 which is Fuel Trim Malfunction fault. The Mercedes CD repair manual was a bit vague as to what to replace. An archive search of the Benz World forums indicated that the Mass Airflow (MAF) sensor could be dirty or need to be replaced. So I thought I would clean it. In order to remove the MAF it’s necessary to remove the air filter box. In hind sight if all you really want to do is clean the MAF sensor it is possible by simply taking the top of the air filter box off and removing the air filter and spraying through the MAF screen at the sensor components. To get to the Mass Airflow sensor you need to remove the air filter box. It is held in place by two bolts toward the rear and two rubber bushings in front. Other items that are attached to it are a flex duct going to the supercharger, various electrical connectors, crankcase ventilation tube and also a vacuum line that needs to be disconnected for clearance. 1. Disconnect the battery ground cable since you’ll be disconnecting several connectors. The battery is underneath the cover/filter for cabin air. You will need to resynchronize the windows and panorama sun roof. 2. There are two bolts that have to be loosened. 3. Disconnect the inlet air duct, there’s a tab on the bottom that can make it difficult to disconnect. 4. Disconnect the vacuum line by gently pressing on the outer ring and lifting. Also disconnect the nearby connector and detach one half of the connector from the stand-off bracket. 5. Disconnect the electrical connectors by pulling on the “T” handles at the front and rear of the connectors. Also unscrew the small bracket that they are zipped tied to or cut the zip tie.