What is this pipe in the photos. Could it be the reason for engine errors? How can I remove it? It has really interesting connection. I tried to pull off but did not come off.

Errors I am getting are:
p228097 the air mass flow in the intake air system (cylinder bank 1) has a malfunction. system function is restricted
p222B84 Pressure sensor 2 has a malfunction. There is a signal below the permissible limit value

 

Is your MAF clean of oil/dirt contamination? It really is a delicate heat sensor that needs to be well in contact with air stream.

If MAF got disconnected/reconnected during Sce you can just clear the fault else clean it to begin with. 🤞

There are many excellent V8 chiefs on this board to help ya disassemble your intake.

 

Thank you for the respond. I am not sure if M278 has MAF sensors or only MAP sensors. I was thinking like you, expecting many m278 experts here to help me but unfortunately no one so far

 

I am not familiar with all your V8 specifics.... actually I know some engines even use both (MAF + MAP)... a bit over killed, right

The DTC suggest you do have a MAF sensor:
"p228097 the air mass flow in the intake air system..."

You can clean and look at MAF data with your scanner... until a chief chimes in.

 

https://mbworld.org/forums/attachmen...ice-manual.pdf

M278 has no MAF, only MAP and regular thottle body....as per document above.
3.5 Liter M276 DES ( stratified ) has MAF they call hot film.

DTC can be generic in its code. One still need to know the engine well enough to understand what it really meant.

MAP ( Manifold ABSOLUTE pressure sensor ) with intake air temperature = MAF equivalent capability

So if the DTCs assumed described the condition correctly as :
p228097 the air mass flow in the intake air system (cylinder bank 1) has a malfunction. system function is restricted
p222B84 Pressure sensor 2 has a malfunction. There is a signal below the permissible limit value

I would read this first : p222B84 Pressure sensor 2 has a malfunction. There is a signal below the permissible limit value
Because of above, then the other DTC is triggered : p228097 the air mass flow in the intake air system (cylinder bank 1) has a malfunction. system function is restricted
My take is, these 2 DTC is saying the same (kinda) thing or cause and effect.

Since there is only 1 throttle body in a M278 or my M276 3.0 , I would think p228097 the air mass flow in the intake air system (cylinder bank 1) means the thottle body.
The term bank 1 is always used if there is only 1 of the item in a 2 bank system of a V engine.

Pressure sensor 2 would mean the MAP at the intake manifold, B28/7 Pressure sensor DOWNSTREAM of throttle valve/body. ( page 38 )
AA. Assume the pressure sensor #2 is bad, surely ECM need to verify throttle body opening angle.
BB. It could be the other way round too, assuming throttle body is defective, the pressure sensor #2 is the verification unit.

AA + BB values will be compared against the real combustion/fueling MAP/TABLE, the one like below :
http://www.formula1-dictionary.net/map_fuel.html


For now the easiest is to verify pressure sensor #2 first ( I hope by position it is easy to remove ).
Don't touch anything yet. Engine OFF , ignition key ON, the pressure sensors all 4, would read atmospheric pressure of the day. 1 BAR ( 1 ATM actually ).

Engine idling, pressure sensor #2 B28/7 would read about 0.3 to 0.5 BAR. ( vacuum )
If you do snap throttle to say 4,000 RPM, pressure would be lower ( more vacuum ).
Remember, this is absolute pressure sensor which also measure ambient air pressure, so 1 BAR is the zero, below it is vacuum. Turbo boost will be above 1 BAR.
A gauge pressure only reads what is above ambient pressure and will read as zero in our atmospheric pressure.

Good luck....

 

This should assist you...........

This is a warm up process of my engine. 603 seconds of it. Car is stationary.



Attached is the complete 24 minutes of the warm up process. Car is stationary except a few meters reversing to be out of the garage.
I did this because I did not use it for 32 days. So special crank-only ( 4 times compression test using Xentry can do crank-only no start ) I needed to do to minimize engine wear and tear from engine oil being drained
down to long and then the long 24 minutes special warm up procedure as per the CSV file.

Use it to see/compare your MAP pressure sensor #2 behaviour.

Have fun.....

 

Thank you so much for all these detailed information. I really appreciate. Thank you for your time and thank you for sharing. I am not sure if I have ability to measure MAP sensors as I only have a basic scan tool (iCarsoft MB2) I am not sure if this tool is capable of measuring. These DTCs popped up after I removed one of the MAP sensors to see if is there any oil leak. I just uninstalled, clean the bottom and install again. Before that there were no DTC.

 

Aha... no worry then when a DTC does register because you remove some wiring connector to sensors/device with key in slot, even without ignition ON.... DTC can be recorded.

Yes icarsoft MB2 can do a lot.

See Intake Manifold Absolute Pressure above : Choose N3/10 engine computer, 44 parameters if for my ECM.
You can choose 5 or 6 so that all shown in 1 page view.

You can't log it and get a CSV file, but you can use its GRAPH mode they call WAVE

In my icarsoft MB V2, DTC clearing is best when we enter the menu of the said computer/module directly.
Say u want to clear engine related DTC, you then must go to the ECM ( N3/10).

Have fun.

 

@S-Prihadi if everyone cared for their cars as you do this would be a very, very quiet forum.

 

We are sincerely fortunate to have @S-Prihadi help us with MB "best or nothing" engineering.
Welcome back Surya!
​​​​​​

 

S-Prihadi, thank you once more for your help. When I remove connector the key was not in slot. It looks little complicated to me but will try to use MB2 tool to see if I can measure the MAP sensors. What should I expect to see as Intake Manifold Absolute Pressure. Yours shows 35kPa is it after ignition on? There is no manual or something for MB2 scanner explaining these measurements, isn't there?

 

Also do you have any idea how to remove the pipe I sent in my first post with 2 photos. What does this pipe do and how to uninstall/install?

 

The 35kpa is at idling, 701 RPM as indicated.
Use my CSV file example and convert the BAR to KPA, it is easy. 1 bar = 100 kPa. So 35 kPa = 0.35 BAR
So at ignition ON engine OFF, you will see 100 kPa thereabout, the ambient atmospheric pressure.

ECM has 4 to 5 fuses or power sources and one being direct HOT/ON at all times, even a mere door opening without key in slot can power up some part of the ECM.
Upon key removal, after ignition ON and even engine was OFF, ECM does not immediately sleep, it takes time.

If you can remove the DTC and it does not come back, all is then fine.

You asked:
Also do you have any idea how to remove the pipe I sent in my first post with 2 photos. What does this pipe do and how to uninstall/install?

I have not mess with a V8 M278, so I am not familiar with it. Its seems to be the crankcase ventilation pipes.
I hope other will chime in. Plastic like that may break, so becareful.

 

Thank a lot for the valuable information S-Prihadi. I will try to use MB2 scanner to read measurements. By the way DTC has gone itself today. I did not do anything. Same driving style, same conditions. Weather was warmer than before, though. I am not sure it will come back.

 

I have a general question, why there are very limited DIY information/videos for M278 in internet? There a many for 6 cylinder one. No one wants to touch m278, I think

 

DTC will go away and become HISTORICAL/STORED status once the problem gone/solved and car has gone thru a pre-deterimed engine operating cycle/s.
So you still can read it and delete it using the scanner.

DTC with status CURRENT is where the engine check light comes from and to be investigated ASAP.
Not all DTC will trigger engine check light, like simple ones wont.

Well, M278 population is not as plenty as M272 / M276 the 3.5L non turbo from the E350.
There are more info on M157, as owners are more itchy handed and drive them hard, being AMG higher power version.

My M276 3.0 TT is even worse, very low engine population.

Also there are 5 kinds of owners.
01. Will only learn of the car only if problem arises, in the DIY sense.
02. Will learn ahead of problems, because he/she loves learning. DIY
03. Have learned a lot thru long term ownership and high mileage use. DIY + dealership workshop
04. Does not want to learn but invest heavily in dealership workshop.
05. Get newer models per 3 years or after warranty expired, does not want any headache.

 

Well said and categorized You are totally right about the profile of Mercedes owner. I would like to be number 5 it is the safest