Trying to get my head around a P0101 error on my 2011 E220 CDI BlueTec.
Tried to search the forum, but was even more confused.

Symptoms:
Sluggish. Low on power.
Slow to accelerate.
Slow to change gear. Stays at high revs for longer. (even when in Eco mode)
Able to force gear change with paddle or stick.
Able to reach normal speed but it takes loooong time.



Error comes up as soon as I start the car as pending. No need to drive the car.
Reset error codes with Delphi and both pending and permanent errors are erased.

Just serviced the car with new oil, filters etc. Air filter was changed. First thing I checked was if I got the box and hose back as it should be.


Cleaned MAF sensor, checked cables to all sensors and cleaned them with contact spray. No sign of damage to cable or corrosion on the contacts.

Used starting fluid around hoses to see if I would get a reaction in case of damaged hoses. No luck.
Got a reaction when spraying in to the air filter so if it sucks air somewhere I should hear it.


Freeze frame from eOBD:
Odometer: 271590 km (168758 miles)

PID/Name/Value Unit
02/DTC that caused freeze frame data/P0101
04/Calculated load value/0.0 %
05/Engine coolant temp/49,01 C (120 F)
0B/MAP sensor/98 kPa
0C/Engine speed/0 rpm
0D/Vehicle speed/0 km/h
0F/Intake air temp/29,0 C (84 F)
10/MAF sensor 0,1 g/s
11/Absolute throttle position/ 86,7 %
1F/Time since engine start/0 sec.
23/ Fuel rail pressure/ 0 kPa
2F/Fuel level input/91,0 %
33/Barometric pressure/97 kPa
42/Control module voltage/12,218 V
45/Relative throttle position/99,6 %
46/Ambient air temperature/ 8,0 C (46 F)
4C/Commanded throttle actuator control/100 %

As the fault code (pending) appears the second the car starts, I would think it should be a sensor gone bad.
Anyone has a list of what resistance there should be on the different sensors?


Going deeper in to the software I can get some real-time data and a DTC that is not possible to remove. Could it be that the sensor is sending out faulty data even without engine running?
“P0101 Air Flow Meter 1 --- Permanent”


Here is some real time data when the engine is of and idling.

Name / Not running / Running idle
Atmospheric pressure / 0.974 Bar / 0,974 Bar
Intake air pressure / 0,976 Bar / 0,975 Bar
Air mass / 636.00 mg/hub / 540,75 mg/hub
Air filter contamination / 0%
Engine speed / 0 Rpm / 830 Rpm
Current injected quantity / 0.00 mg/hub / 3.23 mg/hub
Boost pressure downstream of low-pressure turbocharger/ 0,97 Bar / 0,96 Bar
Boost pressure / 0,98 Bar / 0,97 Bar
Inlet port shutoff /0 % / 12 %
Lambda pre Nox catalyst calculated /0,00 / 6,57

Other relevant (maybe)
Odometer: 271590 km (168758 miles)
Particle filter:
Content of ash in particle filter: 0,91g / 62%
Particle filter, measured content of soot: 4,36 g



Any ideas for what to try next?
Filled the tank a day before the error occurred but there is nobody else with any fuel related problems in the area (rural area). Also checked the fuel cap…
Anyhow bad fuel should not create an immediate error code.

 

that's when Xentry guided troubleshooting comes in really handy.
Intake vacuum seems low... engine off 😄

 

Yes, my first question would have been, what did you clean the MAF sensor with, but with all the info you provided, I will assume you used MAF sensor cleaner. I agree it does sound like it's the issue.

 

I replaced the MAF sensor.
No change in behavior.
Still P0101.

I then blocked air intake with plastic. The engine still run as normal…..
I did se that the hose on left hand side from intercooler collapsed partly.
Removed the hose from intercooler and blocked it. It did suck some air trough the fitting so I tried with some plastic.
Fixed the gasket in the hose as it was not seated after I removed the hose.
The plastic bag got sucked in trough the opening (no I did not loose it…)
When the bag made a perfect seal with the hose the engine stalled.

I thought it could be a leak between the air filter and the intercooler.
To get a better seal from the filter I removed the hose from the MAF and blocked it with a piece of hard plastic. The engine stalled!
I then tried to block the filter again and use some starter gas around the filter box.

In front it sucks in some air. There is also some air getting in between the MAF and the air filter.
I would guess this would not affect the anything as its just air seeping in trough small gaps instead for the big hole in the beginning of the box. All the air is also sucked in before the MAF sensor so it would measure the correct amount of airflow anyway.

Any good ideas on what to do next?

I got Delphi installed and I’m also getting Xentry to do some more digging…

 

Remember that every electrical device needs a complete and sound circuit to complete the job of the device. Good sensor plus bad circuit = problems. 2 MAF sensors with the same results point to a problem elsewhere.

A smoke machine would likely assist you in finding any leaks in the intake system if it's a leak that is the problem.

 

I hope it’s not an harness issue. It’s so hard to locate the fault.

when disconnecting the MAF I get p0113 and p0103. That would indicate that connection with the sensor is working.

As the engine stalls when blocking the air by the MAF sensor I would guess there is no leaking from this point and in to the engine. Any leak in the air filter box should not affect anything as the filter is connected directly on the MAF sensor and there is no leak after the sensor.

There is a lot of sensors throughout the air intake system so it could be any of them.

The error code shows up immediately upon starting the engine so it might be any of them.

hopefully I’ll get my new OBD connector soon so I can go at it with xentry…..

 

Did you ever get the issue resolved i have the same issue

 

How did it go?

 

Would be fantastic if you could put the result. Hundreds of forums about the issue and your one is the exact same as mine but never an answer. I'm close to scrapping my car

 

did you find the fix ?

 

Can you pls double-check your fuel rail pressure ??
See how pressure react to load...

OP only shows zero pressure with engine off and no idling pressure...

New MAF does not correct this very popular fault.

 

Sorry, I don't have information about this code for a Mercedes, but I do have one for my 2008 Duramax pickup. See the attachment and this comes from that attachment

Verify the integrity of the entire air induction system by inspecting for the following conditions:
A dirty or deteriorating air filter element.
A leaking, loose, or cracked PCV pipe and seal.
A loose or disconnected charge air cooler hose or pipe.
A restricted or collapsed air intake duct.
A misaligned or damaged air intake duct.
Any objects blocking the air inlet probe of the MAF/IAT sensor.
Any contamination or debris on the sensing elements in the probe of the MAF/IAT sensor.
A cracked or damaged MAF sensor housing.
Any water intrusion in the induction system.
Any snow or ice build-up at the air cleaner or MAF Sensor.
Any snow, ice build-up, or coking at the manifold absolute pressure (MAP) sensor.
An intake manifold leak.
A MAP sensor seal that is missing or damaged.
An Intake Manifold Resonator with a leaking seal, or a cracked or broken housing


It would be helpful if you could find Mercedes information in a similar format with similar information. As you can see, there are many conditons that cause this DTC to set. I get my Duramax information from ALLDATADIY.com, but I don't have a subscription for my Mercedes. You can get a 1 month subscription for $20.

 

We sold the car with the problems and was told later that they found some problems with turbos and other crap.

MB would probably start replacing parts and hoping to find out what part was broken and then bill you for everything.

 

Hi


Thanka for getting back to me. I'm starting to think turbo actuator but I've explored every avenue so far. Just wanted to solve the issue and go fast again.

 

Everything all clean and clear. Still having issues p0101 pending and then after restart it's then stored with eml light on.