C204 2011 C220 CDI COUPÉ LIMP MODE & EML

[tgl3]

Hey guys,

hope all of you had a great week so far!

About two months ago the EML of my car turned up and being checked by the dealer. No unusual signs beside the Auto Stars/Stop (Eco System) stops working completely at that time. I was told that the Boost Pressure Sensor & the auxiliary battery had faulty (see photo attached) so got them replaced which costs me approx 350 quids. It drove like a dream afterwards until today, this morning, the Engine Management Light turned up again! After I started the car this morning I immediately noticed the engine idle speed is now much higher than it used to be (was around 6-800 RPM but now runs at 1k RPM). Strangely, this time the Eco mode still works but looks like the car goes into limp mode. On the way heading south this afternoon the car was running noisy due to changed gears at a higher rev (always changed at a speed more than 2k regardless the gear selected) than it used to be (1400-1600 RPM); and the car has very sluggish acceleration now. I was thinking of blocked DPF and the car might needs a long run to have the DPF Regen done when the engine light and unusual signs found this morning, so putted a bottle of Redex DPF cleaner before setting off south to have a long motorway run. After 100 mls run the car still under limp mode and nothing changed... Don’t know what’s happened there, anyone has any idea on this?

 

[tgl3]

Hey guys,

quick updates after the car being stuck in the garage for about a week...

Three days ago the car went through a diagnosis and found three error codes (Faulty MAF sensor & Faulty Exhaust Back Pressure Sensor 1 & xxx (sorry can’t remember

flaps not operated )I have been told that the car had a faulty MAF Sensor which caused the other two error codes. The replaced sensor hasn’t arrived until this morning. So got it replaced and the garage test drive the car for a while and handle it back to me said it’s okay for now (420 quids gone). However, on the way driving back home, I can still feel the sluggish acceleration although the Engine Management Light was off. As soon as I arrived home and parked up the car, guess what, the Engine light back on again! Therefore immediately sent the car back to the garage and asked for a quick check. After waiting for a while, they told me that although they found no leak or spilt pipe two days ago when they did the smoke test during the diagnosis, there may be still a pinhole exists which cause the pressure leakage therefor they will need to take apart components under the engine bay to have a throughout check...

It’s really annoying now and don’t know what happened there... finger crossed they can find something and get the car back to normal soon

 

[Tonygw]

HOpe you get it sorted, a decent garage will have a smoke machine that they can use to fit air leaks. They pump a type of smoke into the inlet and if there is a split hose it will be visible seeping out of the hole. HOpe they can do this for you. My boost pipe split and had similar symptoms, they woudlnt have found the hole without the smoke machine.. good luck

 

[HITECH]

Did you ever get this sorted ? Just some info for you. A Faulty Exhaust Back Pressure Sensor will also kick up a MAF and Turbo boost error code giving out false data which in turn screws up your air ratio which in turn screws up your turbo boost. One of the common signs its purely the exhaust back pressure sensor is the car is gutless but still can go up thru the rev range past 3000rpm.