I'm getting DTC P0236 (Turbocharger Boost Sensor A Circuit Range/Performance)
I can feel the turbo "kick-out" as I'm accelerating.
Engine currently has 145k on it.
The red neoprene gasket/bushing, on the crankcase ventilation tube, going into the plastic intake pipe, just before the turbo, easily pulls out, and there doesn't seem to be any provision for a clamp, so I'm wondering if un-metered air is getting into the intake system and throwing off the ECM, or if it as simple as a bad/clogged MAP sensor?
Anyone know where this sensor is on the engine, or have a link to a sensor diagram? I cannot seem to find a sensor diagram online.

The engine had MB emissions component replacement under the MB warranty this past January.
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Hello. I'd advise you against doing anything with the turbo, because that's covered under the extended emissions warranty. If you do anything, MB/dealer will say that you did something with it and they will void your warranty. Make an appointment at the dealer where you had the AEM done and they will diagnose it and repair it for free. Tell them that the car is loosing power at highways speeds when you go to pass other cars. That will narrow it down for them and point them in the right direction.

Looking down the road, if you're going to keep the vehicle, you can always stop by the MB parts department and have them print out the location/part for you.

To answer your question about the 'red' neoprene gasket. That's part of the crankcase ventilation hose that inserts into the Y pipe housing so the turbo can ingest the gases - because it's illegal to vent them into atmosphere. What happens at the same time, oil droplets in those gases are also ingested into your air system and will gunk up your system. You have to install an oil catch can -- ProVent 200 works very well. It will prolong the life of your engine 3 fold. The connection will be loose on that part so even if it comes off it shouldn't throw a code for the turbo. I believe your turbo is defective. GL.

 

I'll buy a catch can, I have one on my son's Audi and would have one on my other cars if the plumbing were possible.

I ordered two MAP sensors from RockAuto yesterday. I suspect the bad sensor is in the post-intercooler charge pipe, but the sensors were so cheap I also ordered the sensor that goes in the air cleaner housing. Someone who worked on the engine in the past left one of the screws out of the intake manifold MAP sensor, so this part has been fooled around with in the past and there is no reason to remove this sensor, even if the charge pipe needs to be removed. I noticed there are separate DTCs for low & high pressure readings, which I'm not getting, and P0236 seems to be a classic case of the ECM not seeing values it's calculating should be seen given corresponding MAP values it's receiving from those sensors; so before I go to get assistance from the dealer, I'll replace the $26 sensors and see what happens. The emissions warranty work done earlier this year, was before I owned the car, so only in the case that I can't fix a problem reasonably, will I get the dealer involved. Thanks Pete!

 

I was wondering what you meant by Y pipe Pete, and now I realize you're talking about the intake pipe between the air cleaners and the turbo; yes, that entire assembly, incuding the MAFs, looks to be brand new, and I'm not touching those MAF sensors, for one thing, they are $175 each, even after-market, and two, they look to be plastic welded to the Y pipe. I'll post my results when the MAP sensors come in and I replace them, they are very easy to get to, and in the event I have to go to the dealer for sometning related, I will keep the originals handy for a swap.

 

Fixed. The new Turbo Boost/MAP sensor fixed the issue.

 

Read my post here. https://www.benzworld.org/threads/m...oblem-p0299.3144646/?post_id=18788678&nested_view=1&sortby=oldest#post-18788678

 

I responded to your messages on your post.