MAF Sensor Nightmare



The clip is held in place by the wings on the thermostat housing. you need to simply loosen the Torx bolts until the clip slides up. Notice the flange on the thermostat housing has a radius that allows you to pull out the temperature sensor without removing the thermostat housing. Very clever those Germans. If you get the sensor at the dealer, buy the clip too. That will insure you don't loose or break the original one.
Good luck.
I was dumb and forgot my VIN number to see how much parts would be, but I am about to head back up there.
Also, I have done mathematics on what the charges will be if I do end up taking it to a shop.
The independent Mercedes shop places their diagnostic fee on top of the service, so that is out of the picture.
I got a quote from a towing company, because all the mechanics have said I should not attempt to drive it. To take it to the Mercedes dealer, it will be $75. The diagnostic is $110, and they remove it if I get it serviced. If I don't get it fixed that's another $75 to bring the car back to my house, which is about $300 total without my car being fixed.
I called "John and Son's" mechanic shop, in which my brother acclaims them very greatly, and he said it will be $40 for a diagnostic. He also recommended a tow truck, but I live maybe a mile away from him, so I wouldn't expect it to be very high in price. I'm sure he'd let me keep the car there until I make any decisions after the diagnostic, because I have developed an owner-client relationship after taking it to him over the AC Compressor/Power Steering Pump whirring mystery.
I am just kind of nervous to take it to a mechanic that doesn't specialize in Mercedes, that is all. But if it really does end up being this Coolant Temperature Sensor, they should undoubtedly be able to do it, considering the simple instructions you gave me!

Have you unplugged the sensor & cleaned the contacts?
See the big what if for me is, that I may do this replacement and nothing happens and my car is still undriveable at my house. Or, I try to replace it and mess something else up like how this all begun from me just simply trying to clean the MAF sensor. I realize that the operation should be fairly simple, but it's just the fact I still have to get someone to taxi me around all over to pick up all of the items needed.
I did get priced $22 for a sensor, and $24 for coolant. Would I need to buy this much coolant if I will lose just a little bit?
EDIT: Also, is it really as simple as unplugging the old one and plugging in the new one? I'll spray it with some electrical cleaner, too.
Last edited by DaODB; Jan 8, 2013 at 09:46 PM.

I have owned a whole series of Opels/Holdens in my life as company cars that use Bosch fuel injection. Every one of them at some time in it's life has started running erratically, overfuelling & coughing clouds of black smoke out of the exhaust. In every case it has been the temperature sensor & the ECU thinking that the engine was cold & in need of mixture enrichment. At least Benz uses a 2 wire temp sensor. In the Opel case they use a 1 wire sensor & expect the engine manifold to make the circuit (earth). In the Opels it is a brass sensor screwed into an aluminium manifold. Brass in Aluminium catalyses corrosion so the sensor loses earth & does not work.
Last edited by Glyn M Ruck; Jan 9, 2013 at 12:40 PM.
The Best of Mercedes & AMG
Saw a old car for about 1200 at a used lot.... maybe looking like my fit... lol
White smoke from the tail pipe seems to be turning up to be Head Gasket failures from what it appears on Google. Not a good sign at all. Even the Carbon Monoxide is odorless, I would say that the smell from the tail pipe has the same scent as any other car. Maybe a burnt plastic smell, which did appear sometimes while I first started the car in the mornings.
I did find an old sheet of the diagnostics a year ago when they replaced the valve gasket covers. Not sure if this would help me at all at the dealer considering the Head and Valves are different.
I am uploading a video soon to give you a visual

The video says that "this video is private"
Please check fuses 48, 53 & 54 in the front SAM (fusebox)
Also check fuses 31, 52 & 57 (Technically it can't be fuse 52 or the car would not crank over) Check it anyway & is it's 15 amp uprate it to 20 amp to get another potential problem behind you.
Last edited by Glyn M Ruck; Jan 11, 2013 at 09:08 AM.


Should I take it for a ride around the back streets of town today? I have been stepping on the accelerator trying to warm it up a little bit while in drive, but the temperature gauge has not been moving. Furthermore, it took much effort to get the U Clip off, and I can't get it back in. The alternator (I believe) is/was blocking the way. Went to about 4 different stores, no one has torx screws. AutoZone didn't even know what a Torx screw was, and the dealership laughed at me! I was just going to attach it to my key ring with a note and leave it for the tow man to drop it off.


That thing above the sensor that is probably getting in the way is the Auxilliary or excess air pump for emissions improvement at cold start.
Just the day after all of this driving, I decided to try to clean the MAF sensor. All went well, until I turned the car back on.
The oil didn't seem to show any discoloration, maybe a little dirty. It was rather low though, and I did the measure on the display, and it said add 2 quarts.
Also checked the coolant, and didn't see any air bubbles, and didn't look like it was low at all.

Try running the car with this MAF plug plugged in first.
Then try running it with the MAF plug unplugged. This takes the ECU onto a default MAP where it ignores any MAF input. If the MAF is damaged the car should run better with it unplugged.
You don't have to remove the MAF to plug & unplug. I'm just using these pictures to help you.
Did the temperature gauge work before? I know on your model you had to select it so you would not look at it every day but you would have got a red screen warning if the car had overheated & the old temp sensor worked. At least you know you now have a good sensor.

Last edited by DaODB; Jan 28, 2013 at 02:13 AM.

What is wrong with the TPS. Don't replace that until you replace the MAF. It might be fine.
I will definitely take the MAF out for the meantime until the new MAF comes in. That drive home was scary, and it was only 10 miles tops! I also believe that the MAF is causing the acceleration problem, so I will be only purchasing the MAF for the meantime.
I will probably be taking the MAF to the local mechanic, not just because I feel like an idiot after breaking it when trying to clean it, but to also clear out the codes. I know about the battery trick, but I suppose I want to do it the proper way.
You live and you learn... and I think my experience was that my head does not belong under a hood!!
Thank you all for the help!


