No big deal- P0170 is most likelythe regeneration valve AKA "MOT" valve- purges vapor from gas tank.

It's located behind the driver's side headlight and it's stamped "MOT" on the top. You don't need tools to remove it.

Take it out, shoot both openings out with carb cleaner really good, let it dry and reinstall.

Should fix it.

Otherwise expect to spend about $150 for a new one. I just did mine last month for the exact same thing. No more codes.

Google search it you'll see it's a common error.

rj0

 

I purchased a can of BG Mass Air Flow Sensor Cleaner $10 Bucks, I removed the Sensor ONLY, but it was very clean, I sprayed it anyway, put it under the sun to dry, I then removed the MAF housing and I sprayed it too! After confirming that all is dry, I put everything back together, I started the car, everything is fine, but the "Check Engine" light is still "ON". I did not erase it, I am now driving to reach over 100 miles and see if it will go away. My office is just 4 miles from home, so it will take a while to reach 100 miles. I believe that the Fuel Filter has not been changed for the last 6 years. I found the Air Filter Very dirty, I went to two auto supply stores and no one have it, and so I ordered a MANN from autohausaz.com, will be in shortly, I cleaned the air filter as well as the housing, vacumed it, was full of bugs, sand, leaves etc. The car runs great and smooth, in fact it starts better than before. By big question to you the Group is: What should my NEXT course of actions be, without making financial mistakes? I really do not think it is the MAF, only because it was very clean already, and I also handled it with great care, and I only sprayed the bottom.

 

Did you remove the MOT valve and clean it?

P0170 is all about that valve. MAF is P0100, P0101.

rjp

 

What is an MOT valve? I wish I knew, I would I cleaned it, last Saturday I cleaned the censor inside the MAF, I also cleaned the MAF housing. But I have no clue what is an MOT Valve and where it is located.

 

Read my 1st post and this: http://www.benzworld.org/forums/w202-c-class/1563090-mot-cleaning.html

 

A million thanks Randy P

Thanks a million Randy, for the past hour I was reading all your posts about the MOT. I think this is the culprit the MOT. I can't wait till I go home tonight and work on the issue in my garage. In fact I may leave early today, cause it is nice and sunny here in VA. I will buy the CRC Throttle Body Cleaner.

 

Thanks a million Randy, for the past hour I was reading all your posts about the MOT. I think this is the culprit the MOT. I can't wait till I go home tonight and work on the issue in my garage. In fact I may leave early today, cause it is nice and sunny here in VA. I will buy the CRC Throttle Body Cleaner.

Just blast the snot out of it with brake cleaner -

It's much cheaper and you can use it elsewhere to clean things.

Reset all codes after you are done. that should do it.

 

I just used BG MAF Cleaner. I removed the "L" shape little black tube/hose, and it was in my hand and I sprayed it several times, and put it on the table for an hour to fully dry, then the other end rubber hose is longer but I could not take it out, instead I sprayed only on the one end, I then sprayed the actual unit on both ports the "IN" and the "OUT" I then put back all the way I found them, I took the car for about 10 miles to do errands, Groceries, dry cleaners, blockbuster. So I started the car at least 4 times and then went home. The "Check Engine" light is still "ON" though! Oh and I did put the end of a long flat head Screw Driver, and I can feel the KNOCK on my fingers, I also touched my ear on the handle, "BOY" I can hear everything, the unit is working. I will by the break cleaner tomorrow, just to have it handy. I do not know how to erase the code. I need help on that please, and Thanks in advance. On Monday I am receiving the Air Filter from AutoHausAZ.com via UPS.

 

Code erase can only be done with OBDII reader or SDS-

it will eventually shut off, may take quite a few start / drive cycles, but eventually it should.

Someone you know has to have one- the port to plug it in is under the dash right in front of your right knee, little door that flips down will give you access to port.

Oh, and ONE LAST TRICK-

with these cars I discovered that if the CEL was triggered by something not normally related to OBD it could be reset by simply turning the car off, then putting the key to "RUN" (don't start the car, let all the lights on the dash stay on) and let it sit there until the CEL turns off.

may a minute, but if the code is non powertrain causing the CEL it will turn off the light.

Weird car, for sure.

rjp

 

Hi again, In the event that I will need a new MOT valve, then who sells a genuine? is it BOSCH ? where did you get yours? I am not sure yet that I need one. I just want to be ready to order should the need arises. I will try your suggestion in getting rid of the "Check Engine" light first and see what happens. One more thing, where is a good Under the hood complete diagram to be able to navigate and understand what is what I am looking at under the hood of all these parts, is there a schema or PDF or even a CD/DVD? or even online for the 1996 C 280 please ? Thanks

 

This morning, I turned the key untill all lights light up, but did not started the engine, I waited for over 1 minute no lights turned off. I then proceeded cranking the engine, so I can go to work. The "Check Engine" light is still "ON"

 

New MOT is $150 and basically a dealer only item. Sounds like yours is fine.

If the CEL is still on after that little trick then there's a real powertrain code- it takes a long while for it to reset itself if you don't use a scanner.

Find someone who has one or just buy one for $20 bux at the pawn shop or a Harbor Freight.... Any OBDII compliant scanner will suffice.

rjp

 

PS the engine in these cars is an M104- any W210 / E320, late w124 / 300e w202 C280, C36 will have basically this style MBZ engine...

rjp

 

I just used the OBD II and found this time TWO codes, the usual one of P0170 but now a new one P1700, I then cleared them. and drove the car for about 10 miles. NO lights so far, let us see what happens. Now I am running normal with no lights on dash.

 

if it flips out again, scan the car.

If NO CODES show up, then do the key trick.

don't reset if there are no codes, don't drive around with scanner plugged in it pisses the car off and the CEL goes on in protest.

I know all about this since I chased my own tail for a month - I would drive around with the scanner plugged in since the CEL always came on but no codes then discovered it was the tester doing that to the car.

rjp

 

Hi Randy P, Is this a good product? Equus Products, INC.
I found it at Amazon for $129 Amazon.com: Equus 3130 Innova Diagnostic Code Scanner with Live, Record and Playback Data Capability for OBDII Vehicles: Automotive

 

Hi Randy P, Is this a good product? Equus Products, INC.
I found it at Amazon for $129 Amazon.com: Equus 3130 Innova Diagnostic Code Scanner with Live, Record and Playback Data Capability for OBDII Vehicles: Automotive

In essence that thing is just a standard OBDII reader with the I/M monitors on the same screen.

Check this one out. Much cheaper- also I have the one on this site for $129- it's fine.

Actron/OBD II code reader for 1996 and newer vehicles (CP9125) | Code Reader | AutoZone.com

Go stop by a pawn shop bet you can get one there for $30 that does some nice stuff. Not like you'll need it often to warrant an expensive one...

PS- do the key trick now and see if it goes away.

rjp

 

I contacted The Brinson Company since they are located next door to me here in Virginia, They said that for my car I cannot buy just the MAF INSERT Sensor, cause it is round in my car 1996 C 280. The sensors only part is rectangular for newer than 1996. they quoted me $250.00 So now I rearened that I will have to buy the whole MAF assembly. Any thoughts ?

 

What codes popped up? Before you spend the cash verify codes. General MAF is p0100 / p0101

Oh and the Maf if that's needed go here

Auto Parts at AutohausAZ - OEM Auto Parts - Discount Replacement Parts, Resources and Car Care Tips

your maf is the "round plug" pre 1996 M104 maf. any maf off any M104 will work with round plug.

 

I did not buy anything yet, I am close but did not. The code has always been the same, it is the code that is now imbeded in my mind 24 hours a day night weekends, my life is on hold due to this code P0170
P0170 fault code for fuel trim malfunction Bank 1 of 1
This code never goes away, I cleaned the MOT purge inlet/oulet, I cleaned my MAF, I replaced the AIR Filter, I replaced the GAS filler CAP. I replaced the OIL filler cap, In January I had my oil and oil filter changed. In February I had my Body Throttle sprayed with BG Body Throttle spray. This past summer 2010 I had a tune up, spark plugs replaced. I shall never forget this P0170 code, and YES my "Check Engine" light is still "ON" and yes I am still driving around with the light "ON" what is strange, is that there are no symptoms, the car runs fine! why don't I ignore that light and go on with my life?

 

I do not understand what pre 1996 M104 means! my car is a 6 CYL

 

M104 is the engine series of this car. Found in a 93 300E, C280 up until mid 96, C36 up to mid 96-

all the same Bosch MAF. So, resetting the codes it came back on after cleaning the valve..

How many miles on car?

 

171,133 exacttly as of THURSDAY morning. Please help me figure it out Randy, the car runs like new though! nothing wrong with the car other than the "Check Engine" light is on. When I use my friends OBD II to erase the light, the light comes back on after 50 miles or so. I am embarrased on keep asking my friend at the office to erase my light, one of these days, he will tell me to buy my own!

 

http://www.benzworld.org/forums/w202-c-class/1292067-wonderful-check-engine-light-2.html

 

Well, you eliminated the cheap / free stuff, so the only thing left is the new MAF- that could be it, wouldn't be surprised with your mileage.

autohausaz is the only real option- they will get it to you cheap n fast- the real Bosch one.

On that note, stay the hell away from Ebay- a lot of those guys just resell dead MAFS they get here and there. Only buy from someone who is a legit dealer like autohausaz

When the maf really gets funky it shuts off the car. BTDT. I have a whole thread on peachparts showing the big fight I had last year with my car. No codes on my deal.

I won, fortunately.

96 C36- random sputtering and stalling- I searched.. - PeachParts Mercedes ShopForum

 

Yes, I will order the MAF from Autohausaz, I am wondering though, what does the MAF has to do with "FUEL" or "FUEL TRIM" I did not see any lines that passes fuel inside the MAF! what exactly does the MAF do? and why is it there? I will also do some googling and see what is the role of a MAF and why my code points to FUEL TRIM Bank 1 of 1

 

measures airflow and adds fuel to the appropriate amount so the engine runs right

When it goes out of whack the other sensors try to compensate but once you get past a certain point it can't add anymore and you get a nice MAF code.

Fck, I hate MAF issues.

rjp

 

I FOUND THE CULPRIT




I open for my final inspection before going to the internet and spend $200 for a MAF, and here is what I have found. There is a rubber tubing that is bent like a half circle that goes onto the MOT, one end is all cracked and, I cannot replace it, because there is a white mini tubing in the center of the half circle rubber balck tubing, I will need to order it. Please help me find the part number. Please review the pictures below. Please help, I am close in fixing this problem. Byt for now and for a TEMP solution I put some 100% silicone caulcking where the crack is.

 

I hope it works. YOu sure you can't just replace the hose with some universal fuel approved stuff from the auto parts store? I don't recall mine having any plastic insert to deal with...

rjp

 

A2024760123 Part Number



The good news is that after that I put 100% silicone around the crack, that cracked tube has been SEALED and therefore the vaccum leak is fixed, and no longer get the engine light anymore, I drove the car for 300 miles and no more engine light. The bad news is that the cracked tube is a unique part that only the dealer sells it, and they want $30.00 plus tax for this small tube, I called AutohausAZ and they do not carry it nor order it, and they do not know who does, so my question is, what other online parts store should I TRY? I know I can get it a lot cheaper than the dealer, but do not know who sells it, Part Number A2024760123 or without the A 2024760123. Thanks

 

Only one bank since it's a straight 6. It's probably still leaking, just very small.

 

I just spoke to the head of the service Dept in the Dealer look here American Service Center | New Mercedes dealership in Arlington, VA 22203
He said that he guarantees me that it is the MAF and none other! Period. He even said that, I can replace it myself it takes 15 to 20 minutes. He even recommended me to buy it from this place around here Brinson Warehouse Locations:

So I have decided to take the plunge and buy the Bocsh MAF. I am tired speculating as to what is the problem.

 

Any update - has the light come back on?

 

No the MAF light never came back on



I now getting a new code P1700 and it is Transmission Control Manufacturer. The MAF original light went away once I replaced the MAF, however, my gas mileage is the same, no change on my gas mileage, most people say that if the MAF is replaced, then the gas mileage will improve, this in NOT the case with me.

 

Happy W202 owner!

I have just bought this car ( 1996 c220) and rebuilt the engine control harness due to the insulation failure. Car sat in palm springs heat for 3 years. I was plagued with this reoccuring P0170 code. I have a OBD|| tool, so i kept clearing the code. I cleaned the MOT valve and it it 'ticking' away and so far ( knock on wood) no reoccuring code.:bowdown: will test tonight on drive home. Now, on to see why gas gauge only works at full or very rarely it will give me an ALMOST accurate reading...