Gents,

I want to share.......
I do not own M272, but since member Tesna here has one and I been studying about it, but I never get to touch or play with the real product, it took me days to realize how
it actually works. This write up will help you guys troubleshoot your M272 Intake Manifold.

I discovered how misleading is the component name used in the DTC description by the ECM ME9.7.
The WIS and the Xentry Test and Actuation feature uses different component name too.

Many surprises when you read on......


The WIS will call this entire unit as RESONANCE Intake Manifold. Good thing they keep the INTAKE MANIFOLD in the description.




A kind of M272 introduction booklet simply call it INTAKE MANIFOLD. I am attaching the booklet.
But here is the good part on its duty or capability....



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Here is the "good" part
When you get DTC from this Intake Manifold, most common one is : CHARGE MOVEMENT FLAP ERROR or MALFUNCTION


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What a joke , the DTC editor loves to confuse people.
The problem is from the broken linkage of the Y22/9 which is the SWIRL FLAP




Do take note that there are 2 component controlling air movement or air charge movement.
Y22/9 group for Swirl Flap
Y22/6 for Variable Intake runner, short/long air path

I find this DTC description as CHARGE MOVEMENT FLAP is simply a lazy azz and if there is no obvious broken mechanical link visible,
you will wonder which one of the 2 capabilities of the Intake Manifold is having this malfunction ?


This is Xentry description of the test for these 2 capabilities of the intake manifold :


If without the Y22/6 and Y22/9 header of the title, you will be wondering what is Tumble Flap, which one of the 2 deserves to be called a Tumble Flap ?
If you are on a 3rd party scanner and no EPC/WIS and no google/MB related forums to assist , you may waste hours trying to figure out what is what ?

So the Y22/9 has now 3 names : CHARGE MOVEMENT FLAP, SWIRL FLAP and TUMBLE FLAP ...lol
Poor soul Y22/6 variable intake runner has no special name.


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Now the technical bits....

Y22/9 Swirl Flap/Charge Movement Flap/Tumble Flap is detectable by ECM when and if it does not move into proper position when actuated by ECM, because it has 2 hall/position sensors at the azz.



A is the magnet at swirl flap rod, B is the hall sensor. From iRepair Autos - Youtube





These are the flaps for the SWIRL action. OFF is open and ON is blades/flaps in action.


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The desired SWIRL effect




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You then decided to test the Swirl Flap Y22/9 using actuation feature of your scanner/Xentry.
Boooo..... actuation is not possible for Y22/9, only available for Y22/6 This is nonsense. Its only a 12V signal to send out. Usually solenoid uses 12V and not 5V.




How about the TEST feature for Y22/9 ?


TEST is not always ACTUATION, it can be physical measurement of the signal using DMM.
They want you to measure the voltage ...LOL


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At the least the Y22/6 Variable Intake Runner ( short-long air path ) can be tested using ACTUATION.



Can we inject 12V for Y22/9 Swirl Flap to test ?
Well you can if you want, but remove the connector to it and don't allow the ECM to get the 12V injection. The power to it must be fused at 1 amp for safety.




So how does the Y22/6 Variable Intake Runner the short-long air path works ?
Its like a road detour, that's all.



This are the flaps responsible for the air path detour. From iRepair Autos in utube



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Now something also very interesting here...............
There is no information on the WIS on how the vacuum actuators plumbing/routing is for Y22/9 or Y22/6.
You only get below from EPC and not WIS




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You have to decode components not named in this page to try to understand the vacuum air flow.




At a glance looking at the EPC for hoses... we will think that the vacuum pump at the Bank 2 ( LEFT ) rear azz is the one powering all the vacuum needs of
the Intake Manifold 3 vacuum actuators 22/6 2 pcs and 22/9 1 piece....WRONG !!!!!






At a glance it looks like.................





Well, we need to look more carefully......




---WILL CONTINUE-----

Thank you Master Surya for this very interesting study!


In depth research of mixed vacuum + electrical + mechanical + EPC + WIS + YT... it is MS! grade.


Our M276 evolution features a plastic intake plenum with similar functions with short/long runners and vacuum actuators. Complete with its built-in oil catch-can up front for overflow.
There's even a blow out cover on the top side.

It was interesting to see how ECU tracks the flap positioning to know when faults are ready for service.

Speaking of hands on service, I am due to remove my intake soon for fresh CPS :
- exercice flaps for smoothness
- empty oil out diaphragm actuators
- empty oil out if intake + front can.
(Last time I was in there I recall lubing one of the actuator shafts).

Thanks Cali for the M276 3.5NA information.

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Lets continue with M272 Intake Manifold.

The 3 vacuum actuators 22/6 ( 2 units ) and 22/9 are SELF-POWERED for its vacuum source, directly from the intake manifold itself, which in a non turbo engine is always below atmospheric pressure, aka vacuum.

The green arrow, what an ugly fitting style used for penetration of the hose into the intake manifold body. Why not place a good bulkhead adapter like red one ?


The green arrow ( Y22/6 or 22/6 ) hose continuation inside the intake manifold.


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So, what are the two vacuum hoses out of the intake manifold for ?
The intake manifold also is a vacuum power source for Secondary Air Injection vacuum actuator needs, thru that Y32 solenoid which is a simple OPEN-CLOSE valve.
B28 is Manifold Absolute Pressure sensor.


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So what does the mechanical vacuum pump at the Bank 2 ( LEFT BANK ) azz does then ?
It is a back up and working in parallel with Intake Manifold, to provide vacuum source for Y32 solenoid for Seconday Air Injection system
That is why you see item 20, two of them, which they are CHECK VALVES or One-Way valve.



Green lane is suction/vacuum provided by mechanical vacuum pump
Red lane is suction/vacuum provided by the intake manifold.

If say the check valve of the red lane ( intake manifold ) failed in open state, what will happen ?
Well, if that happens, the vacuum pump ( green lane ) will then suck air out of the intake manifold and send it back to engine crankcase.
Vacuum pump is always more powerful vacuum wise than intake manifold, it can achieve easy -14 PSI ( near 29 inch Hg vacuum ) for a healthy unit if brake booster not being used ( brake pedal not pushed ).
Intake manifold at best is -12 PSI ( 25 inch Hg vacuum ) during deceleration, usually 16-22 inch Hg vacuum at idle.

What happen if the check valve at the green lane ( vacuum pump ) failed in open state ?
Well, if vacuum pump is still healthy there will be suction tug-of-war between intake manifold and vacuum pump which in most cases intake manifold will loose.
If the vacuum pump small port, the membrane inside it which acts as check-valve and oil stopper too...is torn, the intake manifold would likely win the suction war and will get
lots of engine oil from the vacuum pump small size port. You will then be confused and start blaming the PCV system for the too much oil into intake manifold.
Since M272 is a MAF engine, it is bad if any un-metered air from a vacuum pump entering the intake manifold....its going to be like a small vacuum leak.




---- Will continue---------

The hoses type used in M272 vacuum system is a mess.
Unique bent/curve rubber hoses, mix with hard plastic pipe, adapter for size change....yada yada... so NOT elegant.

From vacuum pump to Y32 solenoid ( air pump switchover valve )




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Allrighty, happy troubleshooting for those with M272........

hello. Thank you for sharing your knowledge with all of us

I’m having an issue with my M272 engine (W212). The tumble flap actuator doesn’t move when commanded, but when I push the linkage manually, the sensor voltages drop as expected. Vacuum pump seems fine — brakes work perfectly. My guess is the actuator isn’t receiving vacuum, maybe a faulty switchover valve or vacuum line leak. Anyone dealt with this before?

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Dang, thanks to your question, I was thinking how to help you troubleshoot, I realized I made some mistakes.
Let's do correction first.


Note 1 and Note 2 is the same information, for two different devices.
These two, their vacuum air source is from the manifold and not vacuum pump.

Here comes the correction :
The mechanical vacuum pump is there to actuate the EGR valves or SHUT OFF Valve.
I wrote EGR because some people call it EGR , the WIS called it SHUT OFF Valve, which is for fresh air injection provided by M33 electric air pump, to inject fresh air
to exhaust system of M272.
The Note1 is vacuum hose from inlet manifold itself to also support vacuum negative pressure for EGR/Shut Off valve. So its a double vacuum source design.
Y32 is the solenoid which opens or close the vacuum negative pressure supply electrically for both the EGR/Shut off valve.
So EGR/shut off valve has vacuum actuator built-in for movement/actuation.



Now, with CORRECTION made, therefore now we know that the vacuum power to move all 3 vacuum actuators of the M272 intake manifold called 22/6 and 22/9 , is purely by the metal
intake manifold own vacuum pressure and not assisted at all by vacuum pump.

I hope all these make sense.

==============


You need this vacuum + pressure pump to troubleshoot.

Let's begin the troubleshooting.

You wrote :
I’m having an issue with my M272 engine (W212). The tumble flap actuator doesn’t move when commanded, but when I push the linkage manually, the sensor voltages drop as expected. Vacuum pump seems fine — brakes work perfectly. My guess is the actuator isn’t receiving vacuum, maybe a faulty switchover valve or vacuum line leak.

Tumble Flap or 22/9 vacuum solenoid ( supported by Y22/9 electric valve) has 3 names : CHARGE MOVEMENT FLAP, SWIRL FLAP and TUMBLE FLAP


Short of doing lots of work removing componenst to make room for your hands to troubleshoot Y22/9 electric valve, here is my suggestion.
You can only access the top of 22/9 ( vacuum actuator ) for now.




So first you test if the 22/9 vacuum actuator is OK or leaking . Remove hose I marked in red dotted circle below for 22/9 and use you mityvac hand vacuum pump to actuate 22/9. ENGINE OFF.




If you can actuate 22/9 using mityvac hand vacuum pump, next we test electrically Y22/9 electric valve. ENGINE OFF, IGNITION ON, use your Xentry.
The hose in red circle for 22/9 vacuum actuator, you connect to your Mityvac vacuum pump, you pump it in vacuum mode or air mode is OK too.
This hose is to Y22/9 electric valve which is a NORMALLY CLOSED unit ( must be N/C ) , when you get Xentry to actuate it, the vacuum or pressure you build up will be lost.
That shows the Y22/9 is working. Failure to create vacuum or pressure on this hose meant the hose is torn.
Failure to deplete vacuum or positive air when Y22/9 is actuated by Xentry, meant the Y22/9 is kapoot.

The next test is the hose from Y22/9 to the intake manifold body which I label in cyan as B, this one you must find ways to access it.....and it wont be possible without some teardown minimum the M33 air pump removal.



To test this hose B, just the hose, one end of it need to be plugged off.

The fitting itself for this hose B at the intake manifold can crack, here you need a smoke machine to test as best method.



Good luck.........

Hi buddy, thanks again for your quick response — you’ve really pointed me in the right direction.

1. I didn’t realize that the manifold generates its own vacuum. I had been suspecting the vacuum pump, but since it also serves the brakes and those work perfectly, it’s been quite confusing.
2. Thanks for explaining how to test the vacuum switchover valve — I just learned that from you. I’ve already tested the vacuum actuators, and they’re all working fine.

Thank you man this is really helpfull

Glad to help.

MB is never clear on how their overall vacuum pump or intake manifold generated vacuum system works, also the EVAP system is not clear.
I mean no flow schematic like how the lubrication system has.

If boosted engine like mine, there is a dual-check valves which has tripple duty ( Boost, vacuum when not in boost and EVAP injection ) which can have a leak and I loose boost, this information its not in the WIS.
Thus its pays to be itchy handed and learn of the car system when it is still healthy.

.

just out of curiosity why does tumble flap malfunction usually manifest with gearbox shift problems. Whats the connection with gearbox.

Tumble flap and its sister 22/6 flaps, is engine breathing control or throttle modulation, which is very important for smooth driveability.
I believe M272 is already a full throttle by wire throttle body, just like M276.
So when you press accelerator pedal no matter how deep, throttle body will only open as much as their MAP ( mapping ) allows, but it shows if the driver wants to drop or add/up gear.
The MAP assumed intake manifold air flaps system is all healthy, and send the go ahead for tranny to drop or add gears as per MAP and your accelerator command.
When the 22/9 flaps failed to actuate properly the engine is then was on the wrong MAP in reality and that can make shift becomes jerky or bad.

I do not know if you have experience with very old cars using analog carburators and throttle is a simple pull wire to carburator from the accelerator pedal ?
Zero computer car and manual tranny.
The smoothness of throttle modulation is a an art in itself and more so when your carburator is semi tuned.....to get the smoothest engine response towards gear changes.
Press throttle too much too fast, car engine will bog down instead of accelerating properly smooth.
Wrong gear aka too high a gear and throttle too much, we get engine knock and engine does not run well.
Our brain and muscles were then the engine ECM and tranny computer equivalent.

Modern cars tried to up shift at soonest moment for fuel economy, as low RPM as MAP allows .
Its not actually easy to do this if it were still a carburated car , I mean with the smoothnest of modern car.
The lower the RPM the less power you have, so any "mistake" caused by 22/9 tumble flap which is low end power provider, unpleasant tranny shifts you get.

In M271.8 engine there is an equivalent Tumble Flap/Swirl Flap, it if misses by some degrees* ( *improper installed, full degrees of travel not achieved ), engine can misfire even at idle.
Imagine your 22/9 is totally dead, it would have worse effect.

Throttle modulation is the key to driving smoothness and unfortunately it is also how/what tranny computer uses as input to down or upshift.

Hi buddy. I had to pull out the manifold. But theres a few things i may need clarification.

after reading a a couple write ups
you explanation confused me abit.

you wrote

ENGINE OFF, IGNITION ON, use your Xentry.
The hose in red circle for 22/9 vacuum actuator, you connect to your Mityvac vacuum pump, you pump it in vacuum mode or air mode is OK too.
This hose is to Y22/9 electric valve which is a NORMALLY CLOSED unit ( must be N/C ) , when you get Xentry to actuate it, the vacuum or pressure you build up will be lost.
That shows the Y22/9 is working. Failure to create vacuum or pressure on this hose meant the hose is torn.
Failure to deplete vacuum or positive air when Y22/9 is actuated by Xentry, meant the Y22/9 is kapoot.Based on the tests I performed using both a smoke machine and a hand vacuum pump:



When I push air or smoke from the hose that runs from the 22/9 actuator toward the Y22/9 solenoid, smoke escapes through the top vent of the Y22/9, because the valve is open to atmosphere at rest.



The system won’t build or hold vacuum in this direction unless I apply vacuum from the hose leading into the Y22/9 (the vacuum supply side) toward the 22/9 actuator—that’s when the actuator responds properly.

Dang, I forgot about the natural vent a vacuum solenoid like 22/9 system must have during non activation of Y22/9. So sorry.

The 22/9 vacuum actuator can only return to its home position ( no vacuum ) when it also has ways to be vented to the atmosphere aka leak on purpose to remove the vacuum.
So the solenoid Y22/9 albeit only two hose nipple, it actually has 3 air ports. Smoke test can verify which part of the Y22/9 body is the vent hole/port.
1 air port/nipple to suction source , the intake manifold
1 air port/nipple to 22/9 vacuum actuator
1 air port without nipple to atmosphere aka vent port <<---- this port is for 22/9 air path

So the test need to be reversed - Version 1. You already did this test, but we do a bit more.
Hand vacuum pump is to be connected to the nipple at Y22/9 which is for the hose towards intake manifold.
Apply power to Y22/9 solenoid using Xentry and the 22/9 vacuum actuator will then works ( starts pulling ). Original hose to 22/9 from Y22/9 must be connected.


Test reversed - but Version 2
The hose at Y22/9 solenoid towards intake manifold remove and keep it dangling but plugged off for vacuum test, but keep open if smoke test.
The hose at Y22/9 for 22/9 vacuum actuator installed
The hose for 22/9 vacuum actuator nipple get hand vacuum pump or smoke machine instead of connected to 22/9 vacuum actuator
Power to Y22/9 solenoid must be applied using Xentry, and only then you can build up vacuum at the Y22/9 dangling hose towards intake manifold.


Test version 1 is good enough to prove the working of Y22/9 solenoid electrically and vacuum separation or maintaining at its valve/s.
Test version 1 is good enough when it has acceptable vacuum decay, that the hose from Y22/9 solenoid to 22/9 vacuum actuator is not leaking
Test version 1 is good enough when it has acceptable vaccum decay, that the 22/9 vacuum actuator has no leak and has enough mechanical pulling power to
activate the internal swirl flap inside the vacuum actuator.
While doing test version 1, see that Xentry is confirming movement of the tumble flap via its hall sensor.

Test version 1, does not guarantee that the hose fitting or the hose itself at intake manifold for vacuum source to Y22/9 is in good condition.
I believe only smoke test can prove fitting leaks with decent certainty.
I mean you can't seal air-tight the entire intake manifold unless you make special gasket to make it air tight, while on the workshop bench/table.

Apology once more for the confusion/screw-up.

ADD :
The y22/9 solenoid uses 12V and it has no polarity, so bench power supply can work too. But you would want to see Intake manifold swirl flap position sensor activated too...right , this will take more work
in terms of wiring extension if intake manifold is not on the engine or close to the engine.


Here is a good video showing few types of vacuum solenoid, but it does not test for the vacuum ACTUATOR venting port we discussed.

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Have a similar (P2004) code with my M273 engine, no Check Engine Light, drives fine, linkage not broken.
I checked with DAS, the lever actuates (vacuum applied) super fast (lever moving to the left when looking from top) but is very slow returning (spring force) to the right when looking from top.
When I move the lever mechanism by hand it returns quickly...
So I can actuate everything with DAS and the end positions (~0.1V/4.9) B28/9 (left) and B28/10 (right) for the tumbler flaps is OK, the only issue I see is the slow return to the non-actuated position, thinking this has to do with the actuator vent, the solenoid (Y22/9) not venting and this throwing the P2004 code?
Or Y22/9 is not closing quickly, allowing air to go into the actuator, preventing fast closing?
This drives me crazy, not crazy taking everything apart as long as no Check engine light and no driving issues... but eventually...

You can see the lever move (center of the video). Right is the default (vented) positon, left is under vacuum (actuated position).

Try this test :

01. Attached a plastic Tee pipe to read vacuum pressure for the tumble flap vacuum actuator 22/9.
See how slow the vacuum loss during de-activation of 22/9. Here you can read vacuum value.
As you said, there could be possibility that : Y22/9 vacuum solenoid is not shutting negative air supply fast enough.

or

02. Use the mityvac hand vacuum pump to test 22/9 vacuum actuator, how fast does it return when the vacuum is vented out by mityvac hand pump and not by Y22/9 vacuum solenoid


I suppose being powered by intake air of intake manifold Y22/9 or 22/9 could have minor oil trace in it, because intake manifold is usually oily due to PCV system,
and very oily if the PCV system went bad. Oil trace could slow things down.

If for M157/M278 and M276 3.0 turbo, Master Tasos have shown many M157 turbo vacuum actuator being oil filled and thus failed to retract....due to bad check valve at vacuum pump.
Yes, the vacuum power is from a mechanical vacuum pump ( also brake booster ) which is an oil bath pump.

Good luck...

Thanks a bunch for this, very helpful.
I will do both. Tried to remove the rubber hose from top of 22/9 actuator (red arrow) but having a hard time with it, will remove where the rubber hose meets the smaller (4mm OD) plastic tube (green arrow), there I can put in a hook to losen up the rubber...
Got a 4mm ID rubber hose to put on the hard plastic tube to attach the hand vacuum pump for testing...
I will also use some electrical contact cleaner spray on the deenergized Y22/9 solenoid to clear out the vent path, then dry with air...

... wondering if anyone had luck pulling out the hose on top of the actuator (red arrow) without damaging it?

Wow, your L shaped rubber hose got hard with age and stuck that bad....
Usually vacuum related hoses are easy to remove.
Usually I use a small round jaw plier and wiggle left and right on the hose, not pull out, but left and right first till it can spin smooth enough....and then I pull it out while also wiggling left and right.
At times I use silicone spray if the condition/position allows....to lubricate a bit between the hose barb and the rubber hose ID
WD-40 has decent silicone spray, food grade : https://wd40.asia/product/wd-40-spec...rade-silicone/

The plier is something like below :

Tried to remove the hose on top with the round pliers, hose broke, could be that it is molded there?
Had some of the hard plastic tube (4mm x 1mm), used that to bridge the broken hose.

Tested actuator with a hand vacuum pump, all good, releasing vacuum fast, linkage going back fast, so the issue is not there.
Pushed some contact cleaner though Y22/9, the vent path, then clean air, that made the linkage return (vent to atmosphere) faster but activation under vacuum is still faster, will try again after the winter...

That L bent hose it is not molded dead to the actuator.
Its just plastic actuator and rubber when hot they marry well .
If metal tee to rubber hose, it is more forgiving to remove as long as the rubber is still decent.

Klifex sell the actuators with the L bent hose. I hope they fit well to M272.
https://klifex.com/mercedes-m272-int...-without-clips

Mine is a M273 engine revised intake manifold with only two (2) actuators.
I would advise against using such round pliers, they are not good, if you can get to it with your fingers (I could not) then it is way better, the pliers do not allow modulation for the lack of a better word.
I pulled the pliers and tried to be gentle, the vacuum hose broke...but no issue, with the transparent 4mm x 1 (PA12) hard plastic tube I had from a previous project, I was able to patch.

Usually the round plier I used on bigger hose hard to reach, because I have not come across small hose being very stubborn.
Small hose in my car are only for vacuum related devices, all easy to remove and a tiny big bigger hose is the EVAP is also easy to remove for mine.

Sometime I use this kind of hose pusher if space allows :

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That's the first picture I've seen showing the rubber hose nipple inside the vacuum actuator...

It MUST have a nipple for hose ID. Otherwise there will be no sealing.
I think its design having a shroud/cover for hose OD is what made the rubber hose stuck at its ID and OD , making it really stuck bad.
All the vacuum hose if rubber, always have nothing on its OD, it relies simply on hose ID and the nipple of the device for grip/friction and the negative ambient pressure a vacuum
provide, which is not bad, easy free 13 psi negative pressure of the atmosphere pushing down on hose OD to secure it, hence no need hose clamp..

Got a 4x1mm PA12 tube on Amazon, same spec/dimensions as the OEM tube used on M272/M273 manifold, only needed ~ 1".
Fixed the tube I pulled apart with the pliers...
My issue started with P2004 - tumble flaps stuck in activated position... what was caused by the solenoid not venting, pulled the hose on the 22/9 actuator and the linkage moved back fast but not when the hose was connected and the vent happens through Y22/9;
Y22/9 solenoid for tumble flaps vent path (deenergized) was blocked > slow linkage return, pushed/pulled more contact cleaner through the pipe and eventually the air vent though (fast vent), not sure what blocked the vent, maybe grease from the linkage sitting on the vent cap?
I hope this fixed it, car now stored over the winter...

Glad to hear the fix.
If DTC goes away permanently, that meant the ECM algo has "timing" in the calculation.
I mean ECM expects when power removed from Y22/9, the position sensor is to react within X second....if too late , ECM then declared DTC.

I read some DCT trigger points, some only allows 0.2 second or 0.5 second of signal loss, depending on the component monitored.