hi all ,
I have a 06 204(646) 220cdi engine which keeps going into limp mode(engine) when i drive it very gently , It can sometimes be felt to judder just before it happens. If you turn off the car and start again its alright untill you drive it gently again. If you drive it hard it goes properly and it wont go into limp mode,Ultimate power seems ok
The fault code which keeps appearing in the cdi3 control module is check charge pressure control (p2359)(boost too high/to low)
It has no codes in any other system ,It feels a bit like the transmission is slipping at the time the fault occurs but once in limp mode it cant be replicated and the transmission shifts ok afterwards, but obviously their is no power (read no boost), but there are no codes in the transmisson(its an automatic!!)
I have checked the turbocharger vane positioner and even renewed it to no avail.It is definately not the turbo (don't ask me how i know!!!!!!!!!) unless the posistioner requires some kind of initalisation after renewing?
I have checked the operation of the egr valve and it seems ok and is not sticking, I think the boost pipes are ok as it develops 20-23 psi when driven hard and i can hear no signs of a leak, the boost has been verified with a mechanical gauge and when the fault is occuring the boost is only about 5 psi and doesen't seem to be fluctuating unlike the engine /trans which can be felt to surge/pulse? for about 5/10 seconds before the engine puts itself in to limp mode.If you detect it starting to happen and put your foot down it will usually stop it from going into limp mode and perform normally.
The engine has 125k miles on the clock and sounds fine.
have any of you experts got experience of this?
All suggestions gratefully received!
Many thanks Colt

 

Hello,I have mercedec c200,1995 year. I would like to ask you for advice.I have problems with the start button,The accumulator is fine,but the car doesnt start,what can be the problem,thank u

 

update for you all!!!!!!!!!!
I have contiuned to investigate this and i can say that the problem on this car is related to the air mass meter or egr valve, I discovered if the egr valve is electronically disconnected that the problem goes away ,I mean i can drive it as gently as possible and it will not go into limp mode.
I interpret this to mean that the surging felt was the egr valve opening and closing rapidly and producing a fluctuation in the exhaust pressure in the manifold and also a fluctuating air mass value sent to the ecu which would then interpret this as a signal to alter the amount of fuel injected. I think its likley that its the egr valve at fault (even though it works and does not visually stick when driven via a star tester) I reason this because when the airmass meter fails it usually affects overall performance of the engine ,I.E it has poor accelaration,and feels like you only have half throttle available. In the case of this car the overall performance was as far as i could tell about what i would expect.
I checked with mercedes benz uk as to the price of both components (knowing full well that i could buy the bosch airmass meter cheaper elsewhere) purely for the record and to see how many they have sold countywide in a twelve month period.(this is a very handy statistic visible to all mb parts deptments when you are not sure if something is faulty) the upshot of this was airmass meter £185 ish plus vat 200plus sold within a 12month period uk wide, and egr valve £270 ish plus vat and again 200 plus sold within a 12 month period uk wide.
This amount of stock movement uk wide indicates something which is a problem on the engine. If the amount sold was 10 in a year then i would think twice about trying it unless it was cheap which these bits are not , based on a educated guess.
hope this helps some of you aviod going straight to the turbo before checking a few other bits out first
regards Cj

 

Before buying either, I'd take the egr off and attempt to clean it.

Here in the states, you can buy an aerosol cleaner specifically made for MAFs as well.

I'd try that before spending that kind of money.

 

Hello Colt,

Have you solve the problem on you MB that lose power when drive lightly? You last post mention on air mass sensor or EGR valve. My Vito 111cdi is having exactly the same problem.. So far I try replace the turbo boss pressure sensor as suggest by my workshop, but problem remain. My turbo unit was replace half year ago and I don't think is turbo problem.. Appreciate you can share some of your experience..

Thank you,

Tang