Tried searching, but all the threads I found were pretty old and didn't really have a solution to this issue, so maybe a solution has been found since?

Anyway, I rarely ever take my car on the highway because I usually just drive to work/gym/groceries etc and none of these places need me to get on the freeway, and Ive been very busy lately to do any "fun drives". But I started taking my car out on the highway over over the last few days and every time I drive at around 120kph or so, the CEL comes on with this error code - P0101 - Mass or Volume Air Flow Circuit Range/Performance.

Ive tried clearing it and it doesn't come back till I go back on the highway doing high speeds.

Does this have anything to do with my Mass Air Filter being clogged/dirty? Anyone have any experience with this code?

Thanks guys.

 

Here is what Benzworld said:

The engine check light came on on my '96 C280. I checked the codes and it reads P0101 - Mass Flow Operating Outside of Range. I reset the code and some time later it came back on again, with the same code. The performance of my car is the same as always, including gas consumption (+/- 23 miles/gal). Does anyone know if this means my Mass Flow Sensor needs replacement...or can I simply clean it?

Has anyone else had this code come up?

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Update - I cleaned the MAF and the problem seems to have gone away. It wasn't very dirty but I guess, dirty enough to cause the computer to throw a flag.

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Remove the MAF from the air intake by undoing the various clips on the air filter and the hose clamp on the MAF manifold. The MAF sensor will be installed in the manifold. Remove it by undoing the two security screws that hold it in. There is a tight fit between the MAF and the manifold so don't be surprised if it seems tight. Once out, the MAF sensing unit will have a ceramic(?) blade coming out of the bottom...mine did not need cleaning there. In the middle of the sensing body unit is a small set of ports (one on each side) to allow air to flow through, over an epoxy coated circuit (must be optical?). The epoxy on mine was dirty. I cleaned it with a Q-Tip and some rubbing alcohol. I know most use Ether but it's what I had available.

Re-assemble and re-install. Good luck!

 

Awesome! Thanks Karo.

I knew that this wouldn't be a major fix...after all my car does love me

But yeah once it gets a little warmer outside, I'm going to change the filter and clean out the sensor and Ill update this thread then with the result.

Anyone else have any other opinions/suggestions?

 

Try checking here to. They have some tips hopefully it will work.

Good Luck

http://www.obd-codes.com/p0101

 

Hi jcnash/karo,

I think I may have encountered the same issue you guys discussed in your forum exchanges.

I purchased a Mercedes Benz used car back in Sept 2011 (C200K W203 Year 2001). It had already done 77,000 miles
I have driven 600 miles since the purchase and the Check Engine Light has come on 3 times.

On each occasion, I quickly connected the OBD2 reader to my car and it gave me a single DTC code - P0101 "Mass or Volume Air Flow A Circuit Range / Performance"

The OBD2 reader also allowed me to collect and record "live data" (total of 60 frames) whilst the engine was running and the following are the results of 1 out of 60 frames

DTC_CNT = 1
FUELSYS1 = CL_FAULT
FUELSYS2 = N/A
LOAD_PCT (%) = between 18.0 and 23.1
ETC = between 72 and 84
SHRTFT1 (%) = between -5.5 and -1.6
LONGFT1 = 0.0
RPM (/min) = between 740 and 761
VSS (km/h) = 0
SPARKADV = between 14 and 15
IAT = between 27 and 29
MAF (g/s) = 3.42 and 3.74
TP (%) = 4.3
AIR_STAT = no results
O2S_B1S12--B2S----
O2B1S1 (V) = between 0.110 and 0.570
SHRTFTB1S1 (%) = between -0.8 and 0.8
O2B1S2 (V) = 0.455
OBD = EOBD

The Check Engine Light seems to come on everytime I drive long distances at high speeds.

For example, if I drive 30mph to my parents house which is about 2 miles away from my house, there is no problem.

However, if I drive at 70mph to London Heathrow Airport from my house which is 23 miles apart on the highway/motorway, the light comes on.

Sounds like I have the same issue that jcnash reported.
Would you guys recommend cleaning the MAF or replace it entirely?

Please note that I had previously had the O2 sensor replaced as it was believed to be the source of the problem. However, this has not been the case since the Check Engine Light has come on at two occasions since replacing the O2 sensor.

Your feedback would be much appreciated

Thanks,

Tony

 

This seems to be purely a MAF problem. Clean the MAF with CRC MAF cleaner. If this is unsuccessful you need a new MAF. If you require a new MAF make sure you get the genuine article. VW/Audi MAF's look identical but won't work on a Benz.

 

^^ Like Glyn said. I cleaned the MAF using specialized "MAF sensor cleaner" that I found at my local auto parts store, and cleared the code using the scanner and the problem disappeared. Btw, I had the exact same problem you described...CEL only at high speeds (highway, etc).

Make sure you remove the MAF assembly before spraying it with cleaner because you dont want the cleaner fluid running down into the air intake tubing. Then let it dry thoroughly before re-installing.

The CEL code will pop up again ultimately, so now part of my "B-service" includes removing the MAF assembly and cleaning. Works like a charm.

I have heard of situations where cleaning didnt work, and the MAF assembly had to be replaced, but try cleaning first.

 

Tonyho8 hey mate, been having this issue for some time now on and off. I bought a MAF from ebay - guy told me and to quote "yea, they don't do much and a rip off for that money" so I bought one. You have the exact same year and model/mileage to me so its this one: ebay: 330453920015 £43.99

Now, I tried this, seemed to work fine for 4 months and then it comes back!

So, first off, buy a can of this: CRC Air Sensor Clean Mass Air Flow Cleaner MAF UK ebay ID 280931163175

Its really easy to undo the two huge jubilee clips, un-clip the connector, gently pull it out making sure you don't put your fingers in the end of the MAF sensor as theres little grills in side.

Wearing gloves, spray the unit inside and soak it, the liquid will run off and evaporate very quickly. DO NOT SPRAY in the electronic sensor. Leave it in doors in the warmth for a few hours then pop it back. From what I know (not a lot!) the little wire you see inside of platinum! and very sensitive.

Then see how you go - to be honest mine lasted 4 months and light came back on again. From all the posts Ive seen they give up around 10years of age of 70k miles..

I think I need a new one. Merc price a whopping £330 - direct from Bosch its £180. My light came on again today. This must be the 8th time. Overall it doesnt effect the car other than perhaps fuel consumption.

Just gutting at £180 from Bosch. Let me know how you get on.

 

Hi tlethere, thanks a lot for the feedback and advice. Much appreciated.

 

Hello ,how did you fix the problem ? thank you