Hey guys,

So there's been a number of threads on the M271 cam sensor, but not much about the M111. I replaced mine today so I figured I'd provide a little info. Mine was definitely leaking, but it doesn't look like too much oil made its way into the harness as there's no oil on the O2 sensor connectors or at the other end by the ECU. Hopefully I'm ok!

So first the obvious: the M111 only has one of these guys instead of two like on the M271. While the parts from the different engines look the same they are actually a little bit different. The M111 version as a larger hole opening in the center. Further, they have different part numbers too. I was given the wrong one initially from the dealer so I had a chance to compare the two (of course the M111 sensor is more expensive than the M271 one - go figure!).

Anyways, here's a run down on what was involved.

Parts required:

Cam Sensor: 111-051-01-77 (73.95 CDN)
Starter Line: 271-150-27-33 (40.55 CDN)
Plug: 111-997-01-86 (3.75 CDN)

There's a bit more involved to get the magnet off on the M111 engine than the M271, just because there is more crap in the way. First thing you want to remove (obviously) is the air box cover. This shows what we're looking once that is out of the way:



The red circle is the coolant sensor. This needs to be unplugged and then removed from the housing using a 19mm wrench. Coolant will come out, so be ready. Depending on how much comes out you will get a warning after you're done re low coolant. In that case pick up some antifreeze agent from the dealer (Q 1 03 0002), dilute half with water, add to the reservoir and you're good to go. Moving on, the blue circle is the coolant hose from the reserve tank. This needs to be removed too.

After that is done, undo the 3 torx bolts holding the magnet on. It should come off pretty easy at this point, but this is where things get awkward: the nipple for the coolant hose is in the way and the cam sensor can't be removed easily.

I had to get a hammer and a chisel to remove the center cap from the old cam sensor. This needed to removed so that the coolant nipple could go through the plug hole in the cam sensor. Make sure you clean up all the scraps of plastic cap so they don't bung anything up.

This shows how the position of the sensor after chiseling out the plug hole.



The red circle shows the next piece that must be removed to get the sensor out. Just undo the 8mm bolt in the middle while holding the round casing (it spins). There are slots on the side that you can grab onto, I used a pair of adjustable needle nose pliers. Note that there is no seal or gasket required between the engine and the magnet.

Now the cam sensor can finally be removed from the engine. Here's the old one beside the new:



It's pretty easy to put back together now. Slide the new sensor down over the coolant nipple, bolt the cam housing back together, move the cam sensor into position and bolt on, and then gently push the plug onto the sensor. I used a punch and tapped lightly with a hammer until it was fully seated.

Finally I stuck the starter line on and it was good to go. Here's everything back together.



The green circle is the plug for the starter line. The red and blue circles are the coolant sensor and the coolant hose from the reserve tank.

Cheers.

 

Weird... I can see them

But... thanks!

 

picasa is annoying... you should see them now

 

Well this weekend I had to replace the cam sensor, cap, small pigtail segment on my fiance's new coupe we just picked up this month----- to my horror it still didn't work and giving a cam sensor error---so I replaced the sensor on top of the head and the one on the flywheel as well, still throwing the code and running irregularly --- reving up and down up and down---

Next step-- replacing the whole wire harness to solve the issue---

In the process of replacing the harness I used the electrical fast drying spray cleaner on very one of the sensors and let dry---- when I went to pull the wires out of the ECU, I found the plug closest to the nose of the car full of oil---THE OIL HAD MADE IT THE WHOLE LENGTH OF THE HARNESS INTO THE ECU

I cleaned the ECU a couple times hoping that it was just hitting the male contacts and would solve the issue----

-- upon finishing the install on the new wiring harness, I gave her a run---

The car ran a little better, not throwing the code yet but didn't run well at all and then threw the ESP not available and secondary air injection code---


WELL TIME FOR A NEW ECU there is nothing else to replace and the car only has 60,000 miles on it--- M111 woes for me --lesson to all DO PREVENTATIVE MAINTENECE

(will load pictures later) BTW Nice informative post but you really should upload the pics to this site, who knows if they will be there a couple years from now for others to see

 

At this point its worth it to try and clean the ECU. Remove it, open it up, and spray it with contact cleaner.

At the very least, remove the ECU and spray the connector with a ton of contact cleaner, wait a bit for it to seep inside, then turn the ECU over and let it sit for a few days on the connector, so any oil will seep out.

Oil doesn't ruin electronics, it creates low-resistance shorts and impedes good connections. A good cleaning may restore them to new.

 

Bumpin' good advice

 

it helps that in 2003 I bought a 2002 m111 wrecked sportcoupe with 8300 miles on the engine whose engine bay is immaculate and unscathed by the incedent--- I have a spare almost everything to toss at my or my fiance's car-

I will take apart the ECU when I get home and clean the heck out of it--it will be quite a process because it is sealed not by screws but the metal aluminum case itself, wrapped edges that are pressed around the back (so it will not look pretty once put back together). In the mean time I will put the ecu from the wrecked coupe in for right now--- Is that ECU where the milage is stored???? i wonder if my car will now read 8300 miles instead of 60,000

 

Excellent DIY. Man, between C230 and you, I'm getting excited with all the tech flying around!

E

 

"Thumbs" is way better. Cerious software. Does everything, and very intuitive.
Great for managing large volumes of photo's, vs. PS which is good for dealing with individual images.

So, WOW, what an awesome writeup! Ha, E's getting hot and bothered reading all this tech stuff! he he
It's funny, but yesterday I searched all over this board looking for exactly that info and didn't find a word, except about the M271.
I would have sworn there was an issue with Crankshaft position sensor as well, no? Is that the 2nd sensor someone referred to? Does M111 only have a cam sensor and no CPS?

As Heir Kranz mentioned, things have happened around here in the past causing images to disappear. Therefore I've taken the liberty of cutting and pasting the above info and images into a document you can save and print at any time. Makes it easier, when you can print it out and have it in front of you when you're doing the work!

It's interesting to note that the extention cable, is an M271 PN.
I'll be checking that today!

I'm curious. What is required just to do the inspection?
Shizo, can you elaborate on that a little?
What was involved in just checking it? Where was the oil appearing??

And also, it's looking like it might be worth draining the rad, so as not have coolant all over. Then assuming it's still good pour it back, or if not replace it!

 

One observation between the early 2002 and late 2002 models---There is sometype of vacum pump on the front of the later 2002 m111 models--it is circled in the picture below--- VAPTECH is the name on it---strange that this was included on the front of the head on later models ???? anyone know it's purpose

 

Weird, I don't have that at all....

I know there was an update done on the M111. It takes the harness and creates a high spot, so the oil couldn't drip down.

Ohh and for the record, I still have my pants on.

E

 

 

People think the cam sensor leaking is an M271 thing, it's on all MB's. The difference being the way sensor is positioned on the M271 with the harness at the bottom it leaks into the harness and this is not a problem for the other motors but still a problem that the cam sensors leak.

 

Really?

I think this might explain why the ECU gets destroyed in the M111 when it leaks vs the M271. The way the harness is designed most of the oil drips down into the O2 sensors on the M271, and very little gets into the ECU.

Its disappointing this is a common failure on all MBs and more precaution isn't built into the engine harness to prevent this.

 

Here is the problem with either one of the sensors-- the oil either in the m111 fills up then runs down the harness or gives a continuous feed in the M271

BTW a tech at the dealership said that one of the leaky sensors acually filled up the interior on another vehicle--not sure if it was oil or coolant but said they had to replace some interior options in the footwell area to the leak and soak up--WOW

 

I'm just trying to figure out how to get the grey plastic cover from the front of the head. My sensor looks shiney though like the 2nd pic.
Might've been replaced already.

Can a dealer give a list of all the parts replaced in the course of the warranty?

 

SERIOUSLY- How do I get the grey plastic cover on the front of the head off?
Searching on EPC not finding it....and it keeps crashing. Dammit!

 

Pops right off. If you are lucky like me, you'll break it, and never have to put it on again.

 

Oil leaking through the terminal to housing interface is not new with German products. There is intense pressure from the Green Party to use natural materials over synthetic ones. The Greens force their ideas of wonderfulness on society by making it uneconomical to make a hermetic seal for wiring terminals. The "goop" that seals around the terminals in the cam position sensor is organic and comes from a variety of suppliers of raw materials. As with any organic product, it is difficult specify purity and consequences of impurities in the product.

The sealant is made in batches, and the manufacturer can trace back which parts were made with a certain batch of sealant. This is why Mercedes has a TSB for certain type 271 motors and not others. They know which range of engines were assembled with sensors that have proven though examination of warranty parts to be more likely to leak.

Ross Perot got tossed off the board at GM when he asked why the company does not spend an additional seventeen cents per car on the transmission pan gasket, so the customers don't need to mop up red fluid off their garage floors. Smilar "removals" have happened at Daimler for management who asked why the company accepted such crap from suppliers for sensors, wiring, and electronic modules. The short answer is that it makes big money for the company and the dealers.

Proper terminal design and potting techniques have been used on aircraft and military equipment since WWII. It is time for engine management components for motor cars emulate the designs that have been holding back the oil for more than 60 years. Anyone who votes for the Greens or Eco-friendly anything gets what they deserve.

 

I also don't have it.

 

I'm happy to report, that I've determined that somewhere along the line, a dealer, replaced the sensor, and installed the
Starter Line: 271-150-27-33. I was able to unplug the cable at the sensor, and not a drop of oil. Thankfully.

I noted that the Starter Line: 271-150-27-33 cable is wrapped around in such a way that the oil cannot run into the line, kinda like an S curve with the cable going up.

I'll snap a pic.

Well definitely something to check when on the trail of a used 2002 Coupey!

And incidently, for those not knowing.
The covers on the engine all just pop off, no screws. Just the grey one takes a little doing.

 

If you pull the cam plug out you will see oil (if you're unlucky!!) Before replacing mine I cleaned out the plug twice, and checked it every other day. Each time I checked it, there was oil again. So if you see oil, the change it right away!

If you're anything like me, then you will think: "I could drain and flush the rad at the same time... but there's a hockey game on (I'm Canadian remember) and I'm feeling lazy". So instead do this: foolishly think you can be really really quick while taking out the coolant sensor and not lose too much fluid... and then curse loudly when it takes longer than "really really quick" and coolant goes everywhere. So much for being lazy. So in short: changing the coolant at the same time is a GREAT idea, unless ur speedy!!

Oh, after taking enough time to get on a first name basis with my parts guy, we discovered that the starter line only comes with the 271 part number. Maybe it's not needed given the different placement of the sensor on the M111 vs the M271, but for 45 bucks I stuck it on. It is a benz after all.

 

update on my delema-- I swapped the ECU with the other 02 m111 and the car would not start--it would not even attempt to start--the part numbers were 2 digits off----DAMN

I opened the case on the oil soaked one and cleaned it with the electrical cleaner 3x and was able to remove all the oil that had seeped into it from the harness which was clearly visible----

THE CAR STARTED RIGHT UP--- BUT IT STILL IDLED BAD

So I need some extra help-- car runs like a champ at every place but Idle--- so what could it be--it is now not throwing any codes and not reving up and down but still sputtering and missing only at idle-- and that "valves hitting the piston"??? sound is still there-- it sounds pretty bad but only once every 30 sec

ANY IDEAS???? I might have to take it in now that it is not throwing a code for me to go after--- BTW new plugs--but have not replaced the plug coils, I guess that is the next step tonight-- what about the O2 sensors ???

 

Was there any oil in the connectors for the o2 sensors?

 

does the cooling system have anything to do with this. i keep getting a warning saying that i need to check my collant level but when i do its just fine.