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W168 A140 A-Class
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Discussion Starter #1 (Edited)
I have just completed cleaning the air mass sensor in my A140, and thought it might be handy if I uploaded some pictures and description of how to do it.

This can cause the engine warning light to go out on its own. I had a bit of trouble getting mine to go out, but managed in the end with Carsoft MB and the OBD cable.

Make sure you have fuel in your car when testing after doing this - I thought I broke my engine, but I had just run the tank dry!


http://gell.servebeer.com/files/airmassclean.pdf
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RapidShare Webhosting + Webspace

Edit: LINKS ABOVE DO NOT WORK: The guide I made has disappeared, so I have started it again and uploaded the photos with brief descriptions. I will complete it as soon as I can.

http://gell.servebeer.com/~tonyjr/sensor/
 

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Hello TonyJr,

Any chance you could repost the above information? The links appear dead.

I believe my A140 is suffering from similar problems and would really like to try this before spending loads of cash on repairs/replacement.

Thanks loads!

Lau.
 

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W168 A140 A-Class
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Discussion Starter #3
Hello TonyJr,

Any chance you could repost the above information? The links appear dead.

I believe my A140 is suffering from similar problems and would really like to try this before spending loads of cash on repairs/replacement.

Thanks loads!

Lau.
Hi,

I can't find the file on my computer which is annoying, so i'll download the pics off my phone again and recreate the pdf guide.

Sorry abut this - I should have made sure it stayed online. Will post again when I have it done!

Tony
 

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A160 W168 /2002
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MAFS & ECU Repairs

At the chance of boring 'A' Class owners ,
there are links on my page 38 which will get you 10% off MAFS repairs , New unit fitted by MB is at present about £1300.00 you can get your unit tested for £35.00 and repaired for about £250.00 plus carriage and VAT you must mention my site to get the 15% discount.

Although there are two companies mentioned only ECU testing repair the ECU portion as well as the MAFS , so if you think you have an ECU problem rather than MAFS it would pay you to sent it to them.

I have no connection with either company and this is a concession to my readers by the managements of the two companies involved.

Bert Rowe's-A-class info. ECU/MAFS Problems, Breakdowns, Symptoms, Cure, Cost, special discounts.
 

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W168 A140 A-Class
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Discussion Starter #6
Hi,

I have uploaded the pictures to my site - as I have been busy, I will be putting the guide back together from memory over the next few days and putting the descriptions on the web page. The photos are pretty much self explanatry as I will post them in the correct order. You need to be careful when you get removing the cover from the air sensors and when cleaning as you don't want to break them. Carb cleaner worked well on mine with some cotton buds to lightly rub it in. Also take care when removing Torx bolts from circuit board as I nearly scraped all the components off :eek:.

Hope this helps!

Tony

http://gell.servebeer.com/~tonyjr/sensor
 

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A160 W168 /2002
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With the greatest respect to Tony, please remember you are dealing with a unit that will cost you £1200-£1300 to replace.
IN MY OPINION there is no need to strip this unit at all, the two glass reads are visible just by removing the Air filter housing and without even removing the ECU from the car, The carburettor cleaner can then be sprayed through the throat/airway and this alone will assist in cleaning of the carbon that tends to stick and burn on the reeds. It may take two or even three goes but it will clean the reeds
I strongly advise do not attempt to clean this mechanically with anything, these reeds are very fragile indeed and if you break them your car will not start/ run again until you purchase a new ECU/MAFS for Mercedes which will have to be coded in Germany to your car this alone takes over a week
for more details please see my page 38

http://www.aclassinfo.co.uk/mypage.38.htm
 

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W168 A140 A-Class
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Discussion Starter #8
that's a very good point lofty - the above steps are just what i had to do to get my own mafs working properly again because there was so much crap on the sensors. i didnt realise that they were that expensive :eek: as i just went ahead and done it.
 

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Hello Tony and others

Thanks for the good pics. My wifes A140 recently stopped and and lost its idle. It starts ok, but the gas needs to be pumped to keep it running. Took it to repair, but they told me that the whole unit needs ( whats in Tonys pics ) to be changed. I was too curious to see whats in the box before changing it to a new new one. I opened it and found the two sensors, the yellow glass looking small plates. The other one was a little bit burned and in the other there was a small scratch, almost broken, most likely thats the reason for the idling problem. Im wondering now if the two sensors can be changed, for me they look easily replacable. Or do i really have to buy a whole new unit ? Would not like to of course not, since the car is already 10 years old and the unit is quite expencive. Anyone knows if there is a way to not to change the whole thing ?
 

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A160 W168 /2002
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I did add above link where you will find all the info you require, all you have to is link and read then make a decision whether you want to pay MB £1300 for a new unit or have it repaired , i don't think you will find replacing the reeds is a DIY job and before you could even try you have to locate a distributor and when you have fitted them test the MAFS to ensure you are getting the correct readings.

For other owners who are interesting in what's inside all the details with photo's are on my site , by stripping this unit you may well create a situation where it is no longer repairable that's means it is going to cost you the price of a new unit , which only MB can sell you and it will have to be coded to your car by MB in Germany which means your car is off the road for as long as that takes.

The photos on my site are of my old unit , when mine went defective one of the first I'd heard of, there were no companies to my knowledge repairing them, I had to purchase a new unit 2 weeks later and close on a £1000 poorer my car was back on the road .

I did insist on getting the old unit back , hence the photos and I have since had it repaired so now have a spare ECU/MAFS for my car, but remember it will not work on any other A class and that applies to the units for sale on e-bay as well, don't confuse that with adverts where, companies are offering your own unit repair, namly ECUtesting , who do a good job.but as far as I'm aware only ECU testing can repair the ECU portion of the unit. New price 11.2010 £145 mention my site for the large discount.

Bert Rowe's-A-class info. ECU/MAFS Problems, Breakdowns, Symptoms, Cure, Cost, special discounts.
 

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Hi, Google found this thread and I've registered to ask for your help if I may?

My car is a UK spec A160 LWB Avantgarde, serviced regularly.

I've been driving around on muddy, wet Norfolk UK autumn (fall) roads - the rain has been spectacular for the last few days.
A couple of days back the "engine diagnostics" light came on (not oil, water etc.). Oil and coolant levels are OK.
The car seems to be running fine - no detectable difference in performance idling speed, revs or overall 'note'. To all intents and purposes it's driving normally.

The car has been checked over by my local Independent Merc garage, who I trust and service the car with Merc trained mechanics and original Merc parts. The car was "B" serviced about 1000 miles ago mid August.

They've done a "Star Diagnosis quick test" and "checked engine live data" and "Record fault codes and clear". They're saying the problem is in the Air Mass Sensor, quoting £460 (inc tax and labour) to remove the unit, send for repair and refit or £1200 inc. for a new replacement from Benz.

I quizzed them for a bit more detail and was told the problem was causing the engine to run a bit rich but otherwise wasn't doing much else.

I've read with interest Lofty's page and SVC .

I used to maintain my first car 10 years ago but bar fitting stereos and dealing with an airbag warning light fault on my partner's MINI I haven't popped my head under a bonnet in years.

A few quick questions.
1 - What's the worst thing that could happen running the car with the fault?
2 - How complicated is it to remove the air filter and clean the sensor, I don't want to begin then discover I need specialist tools or expert mechanical skills.
3 - If I successfully clean the sensors, will the engine diagnostic light go out or does it have to be reset with a diagnostic tool?

Thanks for your help!
 

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CL500, E430, SLK, Subaru...
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A few quick questions.
1 - What's the worst thing that could happen running the car with the fault?
2 - How complicated is it to remove the air filter and clean the sensor, I don't want to begin then discover I need specialist tools or expert mechanical skills.
3 - If I successfully clean the sensors, will the engine diagnostic light go out or does it have to be reset with a diagnostic tool?

Thanks for your help!
I managed to take the whole throttle body unit out and sluice the lot with carb cleaner, following the guides here, Lofty's site (though mine, like yours, uses the simpler design brought in with the facelift cars), and the Haynes manual. I have a toolbox of sorts, mostly biased towards cycle maintenance, and I had it all apart and back together in a summer afternoon.
 

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A few quick questions.
1 - What's the worst thing that could happen running the car with the fault?
2 - How complicated is it to remove the air filter and clean the sensor, I don't want to begin then discover I need specialist tools or expert mechanical skills.
3 - If I successfully clean the sensors, will the engine diagnostic light go out or does it have to be reset with a diagnostic tool?

Thanks for your help!
Well I've removed the air filter and sprayed the Air Mass Sensor with liberal amounts of "Wynns Carburettor Cleaner" following the instructions at SVC, Lofty's guide and a newly purchased Haynes.
I can recommend not breathing that stuff in as the back suggests irreversable respitorary damage(!). Despite using it outside and avoiding breathing in, it's necessary to stick your head quite close in to see where you're about to spray then removing your head to actually spray. On the subsequent sprays I definitely got some breathed in and it's not pleasant.

Question 1 - On a difficulty rating I would consider it easier than changing a wheel - a few torx to undo, slide the air filter holder out, put the air filter carefully aside (I wrapped it in a clean plastic bag) and a spray. Then the reverse. Definitely not a skilled job if you're not removing the air filter housing itself.

On Question 3 - The reeds are as clean as they can be from an external application and as before the engine is running OK. I see from Lofty's page that earlier models won't reset the light by themselves...
Note. If your car is pre 2000 it may well be that only a garage with 'Star' Diagnostics equipment can clear the fault from the ECU memory. Even if the light does extinguish the fault code for the defective ECM will stay logged until it is cleared. It will have no effect on the running of the car.
It would obviously be helpful to know if the problem is actually sorted out without paying to have a diagnostics check - it would be even better to have the light extinguished in case my financial circumstances change and I can afford to replace the car at some point.
I'd expect my car (1st registered Dec 2001) to be past that point, but is there any way to tell?

PS Thanks for all the advice and guides.
 

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A140 MAF sensor cleaning. 2002

Hi, I would like to try and spray clean the maf, but the link above on Tonyjr' s post no longer works, and loftys page is great, but the photos show an A160.

Does anyone have any pics of the location of the maf sensor so i can spray, if that fails to work i will have to remove, to be fixed.

many thanks
Craig
 
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