Hi, I drive a 2009 c300 4matic w204 m272 engine
Recently my drive belt broke off, had to drive for 10 km to stop somewhere. Got the car towed to my house, lucky for me I knew the belt was wearing because of noise so I had ordered the parts before this occurred. Replaced the drive belt, tensioner, guide and idler pulleys. Turned the car on and I have these codes p0172 and p0175 which means that engine banks 1 and 2 are running rich. Also get p0128 saying coolant thermostat is below coolant regulati ng temp.

In addition to the codes, my car idled rough, revved spontaneously on cold starts from 600 rpm jumping anywhere to 1000-2000 rpms in bursts. This would last 10-20 seconds before stopping. Even when at stop lights and foot on break the engine would rev slightly. Braking system felt stiff and heavy when coming to a stop. Driving from a stop also felt heavy and the pedal acted almost as if it was lagging and then suddenly went with a burst. Not smooth at all from a stop. Anyways. Took it to authorized Benz shop here in Calgary ("German Car Specialists"). They ran diagnostics and came back with basically this: the intake manifold actuator rod was broken, they showed me a picture that showed the rod displaced from the lever. They quoted me $1600 for a new manifold and labour. I said hell no because I'm not an idiot. There are repair kits available for the intake manifold on m272 engines. Anyways this cost me $500 just to find out the problem. I took the car home and took off the secondary air pump so I could peak at the front of the manifold. I could see the rod wasn't attached to the lever, I managed to reattach the rod to the lever. Put everything back. Turned car on and viola no codes except for the p0128. Have been driving the car for a couple days now, in terms of all the driving problems mentioned earlier, everything fixed. Except now the p0175 and p0172 came back. I checked the intake manifold and all operations there are running fine. The flaps open and close like they should.

Now I need help with what might be causing these two codes. MAF was checked and it is running fine. New coolant thermostat is ordered and will be put in soon so hopefully that fixes p0128. Could this also potentially fix the other two codes ?

freeze frame data

: Calculated Engine Load Value : 51.8 % : Engine Coolant Temperature : 72 °C
: Short Term Fuel Trim Bank 1 : -14.8 % :
Long Term Fuel Trim Bank 1 : -20.3 % : Short Term Fuel Trim Bank 2 : -14.1 % : Long Term Fuel Trim Bank 2 : -22.7 %

: Intake Manifold Absolute Pressure : 41.0 kPa : Engine RPM : 594 rpm
: Vehicle Speed : 0 km/h
: Timing Advance for #1 cylinder : 10.5 °

: Intake Air Temperature : 10 °C
: Mass Air Flow Rate : 6.36 g/s
: Absolute Throttle Position : 12.5 %
: Commanded Secondary Air Status : 0
: Run Time Since Engine Start : 691 seconds : Fuel Rail Pressure : 390 kPa

: Commanded Evaporative Purge : 0.0 % : Fuel Level Input : 92.5 %
: Barometric Pressure : 90 kPa
: Control Module Voltage : 14.041 V

: Absolute Load Value : 36.1 %
: Commanded Equivalence Ratio : 0.999 λ : Relative Throttle Position : 1.2 %
: Ambient Air Temperature : -6 °C
: Absolute Throttle Position B : 12.5 %
: Accelerator Pedal Position D : 5.9 %

Any help is appreciated. Thanks

 

A new manifold is about $600 and not overly difficult to replace. And you can buy a new arm kit made from aluminum that is a couple hundred I think. Still the manifold has to be removed to do that. Buy the new arm and fix and clean your manifold.


Do it yourself. (if that is the problem)


http://www.pelicanparts.com/techarti...ld_Removal.htm

 

https://www.eeuroparts.com/blog/1692...manifold-woes/

 

The intake is not the problem. As I said the arm was not broken off it just slipped off the joint. Anyways ordered a new coolant thermostat. Hopefully that will also resolve the p0175 and p0172 codes. It definitely should resolve the p0128 code.

 

Sorry, I misunderstood your problem. I thought the arm was broken.

 

I am looking into this as well, but when I found Mercedes Nomad's comment on this video regarding the metal manifold arm it scared me:


"the person who designed this part should of looked a little deeper into why the bracket breaks before engineering and selling it. The bearing caps inside the manifold that support the runner flaps crack and cause the rod to pivot out of place. This causes the runner flaps to wear into the aluminum manifold on the inside creating a giant hole inside. In many cases if you look in the back there is also a hole to the exterior aswell. Once it wears enough the rod finally breaks inside and gets stuck. Finally the push rod on the outside tries to push the rod via the part you are selling and once it can not it snaps on the outside. Will replacing this part stop the check engine light. YES. Why? Because you are now forcing the rod to move again which will allow the flap sensors to read positioning again. WHY YOU SHOULDN'T DO THAT? Because the engine is a giant vacuum and the intake is the inlet. If the flaps are wearing holes in aluminum where do you think the metal is going? INTO THE ENGINE! So when the intake finally gave up and broke the aluminum stops wearing out because the rod is not moving. INSTALL THIS PIECE and what HAPPENS? You force the rod to move with more force now because its metal and create an even larger hole inside and on the backside of the engine." - mercedes nomad

I wonder if anyone has had issues with their metal manifold arms? i should probably just create a new thread..

 

hey I’m also in Calgary with the exact same issues, I know this is old but it would really help me out if you or someone could tell me what resolved this for you? Did the P0128 resolve your P0172 and P0175 codes after replacing temp sensor???