Glyn M Ruck

I strongly recommend using the genuine Bosch heated O2 sensors. Universal crap in my experience always gives trouble on these cars. You don't have to buy them from a dealer. Buy them from RMeuropean etc.

enap66

Well, I think you're right on that. I will go with genuine on this car. I'm going to sell this thing after I fix it. It needs a battery and an oxygen sensor as well as a revamp of the front suspension. All in all, about $600+ bucks if I do it on my own. This car was my wife's but she's no longer here and I've been using it but I'd rather have a toyota truck or something a little less expensive when it comes to repairs! Thanks for the answer. How about the other question? Any advice on that?

Thanks!

Glyn M Ruck

P0173 = Fuel Trim Malfunction (Bank 2)
P0175 = System too Rich (Bank 2)

Bank 1 = 1, 2, 3 cylinder (fuel door side/passenger side US)
Bank 2 = 4, 5, 6 cylinder (drivers side US)

OBDII/CAN regime dictates that Bank 1 is always the bank that contains Cylinder 1

Your fuel trim is monitored by the upstream sensor. The downstream monitors the effectiveness of the Cat.

It's 22mm

enap66

Great answer. Thank you so much. So I need to clean or replace bank 2. Will do. Thanks for your help, you're very knowledgeable about this car.

enap66

By the way, I bought something very similar to this here pictured socket. It fits but I can't find anything to attach to it that gives me enough room to turn. Not only do I not have enough room to turn but I don't even have enough room to get something up there (like a ratchet)! So although I can fit the socket up there, that's about all the room and nothing else will fit! Could benz make this any more difficult of a spot? I don't think so. Really. So what do you use along with this to get it off? Thanks!

enap66

I am going to be replacing the front struts. There are 2 kinds according to sears auto. There is the Monroe Sensa Trac and the KYB Gas Shock. Has anyone had experience changing these out?

enap66

Glyn,

Do you recommend removing the exhaust pipe/cats to gain access to the upstream oxygen sensors on my C240? I don't see any other way? Thank you.

Glyn M Ruck

No - use a crows foot spanner with a long or jointed drive or a hammer

Glyn M Ruck

Here is the genuine Benz tool for the M112 engine- Some people find a shifting spanner easier than a rachet, swivel & long drive. You do the upstream from the top & downstream from the bottom. The genuine tool is very similar to the generic that I show above.



The front struts are SACHS-BOGE. The only other brand I have experience with are Koni yellows

Glyn M Ruck

Here you go on strut replacement

enap66

You're the best! Thank you!!!!

Also, are you saying I approach the 'upstream' from above the car, looking down from the engine? Sure, I can try that.

enap66

One more question on this strut stuff. Tell me if I'm correct in needing the following:

*strut assembly front
*strut bump stop but not necessary
*shock mounting kit
*strut mount

I would think that all of the aforementioned would be included in the assembly. Do I need all of this? Thanks again and that concludes questions...

well, for now.

enap66

Here's a thought. Unplug the connector and slip in an offset box 22mm wrench. What do you think?

Glyn M Ruck

Yes - if you can get it to fit & it helps. I have always pulled the upstream sensor on the M112 from above. I have not tried the same on an M272 with the quadcam heads. Access is probably worse on that.

If you are going to sell this car you just need struts for front & any rubbers that look damaged.

enap66

Thank you once again!

enap66

So the strut assembly kit and any damaged rubbers, nothing more. Got it. Thanks!

enap66

Alright folks, after tooling around with trying to get this darn upstream o2 sensor removed for a couple of days, hopefully I can save some of you the trouble with what I've learned. Here are a couple of photos along with some instructions on how to get this thing removed before blowing up the car out of anger or flying to Germany and going postal on some krauts at the benz factory! Okay, you ready? Just follow these instructions and you'll be okay. I promise! First off, you want to get yourself a 22mm offset box wrench. You can by them in a package or individually. If you have a harbor freight in the area, hit them up, you won't be let down! For $12 bucks, I got the set in the first picture. MAKE SURE you purchase the offset wrench, it's the only one I was able to wiggle in there and still have leverage to push on! Okay, next you want to disconnect the o2 connectors. If you follow the actual wire, you'll find that it loops up a bit, about 6 inches (if you're laying underneath the car with the top of your head facing the back of your car and your legs sticking out the front end of the car. we're talking about the upstream o2 sensor, bank 2, which is on the driver's side of the car.) so you're going to want to reach up and dislodge it from the clips it's clipped into the engine with. Got it? Next, you want to pull the wire down so it's dangling next to your head. Then, you want to take this stinkin' pain in the *** bank 2 oxygen sensor wire that is dangling next to your head and feed it through the opening on the 22mm offset wrench. Now, this is important. The wrench is bent a certain way, as are offset wrenches. You need to feed the wire through but make sure you do it correctly. You'll know right away. You need to refer to the next picture as reference. Once it's in, you're able to wiggle the darn wrench onto the little ******* sensor. The bottom of the wrench will be facing the ground, close to your head. At this point, you can roll out from underneath the car and go to the passenger side. Sit down on the passenger side or sit down in front of the passenger side tire and slide your body underneath the car so that your left leg is pushing against the wrench that should be firmly fit over that little no good for nothing sensor. Next, hold on to the tire or the strut assembly or anything that gives you leverage and push with all your might. BE CAREFUL NOT TO KNOCK THE WRENCH OFF EVEN THE SLIGHTEST BEFORE PUTTING PRESSURE ON IT WITH YOUR FOOT! IF YOU DO THIS, YOU'RE APT TO POSSIBLY KNOCKING IT OFF JUST ENOUGH TO STRIP IT- AND THEN YOU'RE REALLY SCREWED! Anyway, that's what does it the easiest. If I'd known this, I'd had been done with the removal of this stupid thing in minutes. I hope this helps! Good luck and if you follow this, you'll be fine. And to those who helped me on this site, thanks- I hope return the favor. If this doesn't work, I suggest buying a lot of gasoline, pouring it on the automobile, get some distance between you and the car and torch it. That was next on my list if this didn't work.

lars

Or you could just follow Glyn's advice and buy a crowsfoot wrench instead. It makes the job easy, though, as he says, you'll need a long drive extension. I bought a set of crowsfoots (crowsfeet??) to work on something Italian and find enough uses for them that I've never regretted having them in different sizes. A crowsfoot is, for example, the best available tool for the dreaded door hinge adjustment task on a Lotus Europa.

enap66

Yes, if it has a bend in it. And if you're going to use rachets, beware. They generally have too much play in them for that tight an area.

Glyn M Ruck

I'm delighted you are sorted. I have never had that much trouble. The damn things can seize in quite badly. Note the hammer marks on the Stahlwille crowsfoot.

rkrchilumula

hi

I am a new bie....any help would be appreciated.
I have the CEL on and it is the pre-cat or upstream O2 sensor. My mechanic gave me a quote for 205$ and dealer for 315$. I found on amazon for 88$ and 102 $ down stream and upstream...

http://www.amazon.com/Bosch-16272-Ox...=pd_sim_auto_1

http://www.amazon.com/Bosch-16268-Ox...=pd_sim_auto_1

Readin through above someone mentioned the wire is short and connectors wrong... so should i just buy the down stream sensor (i need upstream) and the problem is solved or do i need some modifications on the connectors if i buy down stream sensor..please help me or point to where i can buy the correct one...

thanks in advance
ravi

casper_c230

So what's the answer? Which Bosch part number is for the upstream and downstream sensors? I'm particularly interested in the upstream one since everyone said that the wire was too short. Please respond. Thanks.

casper_c230

I think it's 17161 at least according to some websites I saw. Can anyone confirm?

casper_c230

Well, I bought this one and it looks like it might work. I won't have any trouble removing the upstream o2 sensor from the cat, but I'm wondering how the plug part is removed from the engine. It looks like it snakes through pretty far and is NOT visible from the top nor the bottom. Mirror's my only hope I guess. Any thoughts on whether the upstream o2 sensor should be removed from the top or the bottom? The 02 sensor itself is definitely visible and accessible from the top - just not sure on the other end.

Thoughts?

Glyn M Ruck

Personal choice dependent on your toolbox. The dealers do it from the top. I've only ever done it from the top. Some prefer the bottom.