CLK MAF(Mass Air Flow Sensor) Failure

[moveitall]

I have just had my CLK 230 kompressor go in to my local MB dealer in Swindon, with a miss fire and acceleration problem. Anyway they inform me that it costs £290 approx for the MAF component and a total of £490 to diagnose and replace component. My CLK is a 1999 version with a total of 23000 miles todate with complete service history. I find it disgraceful that this item should fail after only short mileage.
Has anyone else experienced the same problem and was it as expensive to rectify? Also, rather disconcertingly it did not show up as a malfunction on the dash board display?
Any feed back welcome! :(

[guydewdney]

try http://www.bba-reman.com/air_mass_meters.htm ?

yes - known issue. esp if air filter not done right / oily etc etc

[dkents]

My '97 E320 suffered an air mass flow sensor failure. The Check Engine light came on. The dealer replaced it for free under warranty even though the car was seven years old at the time.

I have found overall reliability, with the exception of the drive train, to be poor in my car. There is something going wrong every 6-12 months that requires a $200-$300 trip to the dealer.

[jberks]

Hi,
I agree, these expensive components failing so early is appalling. Maybe we should all gather together and hassle Merc for a refund as they are clearly shoddy quality or have a serious design fault. My 2000 E240 (42k miles and fmbsh) had a failed air mass sensor and oxygen sensor last month. The bill was just under £500, plus £75 for the diagnostic. Prices quoted over the phone didn't seem too terrible until I realised they were ex vat !. And that was for a specialist as I only use the dealer for servicing to keep the corrosion warranty up to date.
It's interesting that a dodgy air filter can kill them, but as it's generally the same guy fitting the sensor as the did the filter, I guess we aren't going to find that one out!

[guydewdney]

a maf sensor is just a timy thin strip of (i believe) platinum.

an electric current is passed through it, casusing it to heat up. as metals heat up, the resistance increases. as the air flows over it, it cools it, reducing resistance.

so - low air flow = high resistnce, large flow = low resistance.

the ecu has a 'burn off' program built in, so that after the ign is switched off, it really heats it up (glowing red hot) to burn off any deposits.

maybe the burnoff bit isnt good enough?

[mjtray]

As other posters have mentioned an air-mas sensor usually packs up after being contaminated with dust etc, which won't burn off the air mass wire.....leaving an air filter in for too long can cause this and being sloppy when changing the air filter can also cause contaminates to get sucked into the air mass sensor when you restart the engine.

The air mass sensors are made by Bosch and you can pick them up cheaper from a Bosch agent.....they take about 5-10 minutes to replace, depending on how long it takes you to flick two catches to detach the MAF.

I have heard of somebody spraying carb cleaner into the MAF which cleaned off the oil/dust residue on the wire and his car went back to normal.

[moveitall]

I wish to express my thanks to those of you who responded to my dilemma over the MAF failure. Anyway I've decided to take the matter further and have written a letter to: Dermot Kelly, Director at Mercedes Benz UK in Milton Keynes. All they have offerred so far is a 10% discount on the repairs. However, as I use my car to go abroad and cover several thousand miles in one go, I am extremely concerned that this might happen again and I am seeking some form of recompense should it fail again or at least an explaination for its failure and a refund!?
This is the third electrical failure I have encountered with this car, and for a so-called prestige marque, one failure is too much.
So I implore all Mercedes owners to vent their anger at Mercedes-Benz UK direct. Keep the comments coming!

[Richard Murray]

Hi

Had a similar problem with my 80 Avant TDi with 135,000 miles on the clock. Given the age of the vehicle I opted for a refurbished part at £75 plus VAT. Unfortunately I had to pay 4 hours labour prior to that because they tried the turbo, full diagnostics, etc.

I agree that 23,000 miles is shocking, but if Mercedes are anything like Audi - want they can't take into account is how the vehicle is driven, stored, atmospheric conditions, etc. That's their get-out-of-jail clause.

Richard

[500sl]

Hi

Had a similar problem with my 80 Avant TDi with 135,000 miles on the clock. Given the age of the vehicle I opted for a refurbished part at £75 plus VAT. Unfortunately I had to pay 4 hours labour prior to that because they tried the turbo, full diagnostics, etc.

I agree that 23,000 miles is shocking, but if Mercedes are anything like Audi - want they can't take into account is how the vehicle is driven, stored, atmospheric conditions, etc. That's their get-out-of-jail clause.

Richard

You really talk a load of giberish pal.

[Arnie]

Well, I have seen these sensors fail on many cars at around 20,000 miles or less and yes, they are all made by Bosch- at least for German cars, so I don't think that you can realy blame MB for this.

H o w e v e r... The fee for diagnostics is outrageous and that is what you should complain about.

With the symptoms you describe, the MAF is the first thing that a good mechanic should check. Added to which, a dealer technician would have the assistance of being able to read the fault codes for the STAR diagnostics unit. This will also give current readings from all the sensors.

So, accept the failure and cost of the sensor- these things happen- but complain about the £490 to find the "simple" problem. After all, that's why one is supposed to go to a dealer, because of their greater knowledge of the cars.