zebra100

My wife has my C240 2003 twice engine shut down in the middle of road. And both time she claimed after long hot driving in heat weather. It would not start immediately, like the whole thing is dead, but electic lights all fine (thus eleminate battery, alternator problem), but after cool down a bit, it will start again. I checked afterwards, everything seemed alright. But after the second time my wife stuck on the road in Las Vegas smothering weather, I was already in big trouble.

I posted it here and immediately got response from samaritrey (thanks to him) to a CPS problem. Did a search and found W203 was notoriously bad on this catastrophe. And the dealer charge you $400 (ouh!) for that. so I decided to DIY.

samaritrey gave me the http://www.autohausaz.com/ and cps from german original oem only $31 plus shipping. Same thing dealer 120 and genetic parts store 90 something.

Now the major problem, all the DIY from forum are for W211 or other models and the position of the CPS is little different, and it took me about 4 hours to get it done, and mainly to figure out where the hack this stuff is.

I took the pictures for the procedure, but I need to figure out a place to upload these picture.

Mainly, the space is very small: my hand is medium and very flexible, and I felt very difficult to reach there even after dismantle the electric hose and a engine part. so if your hand is large, forget about to reach from top, go bottom: I think one guy here for C32 use the bottom procedure which I prefer not.

Tools:

E8 E10 Trox socket with 1/4 wrench plus flex head extension, with a 6" extension bar (longest can found at Checker) plus my 3" extension then just enough.

First, take off air filter assembly.

2. use E10 with 3/8 socket wrench loose the electricity hose fixture. Then you can reach from behind to the CPS plug, which your hand has to literally push the firewall back a little to squeeze in.

3.trace on line from the electric hose cluster you just loose to the plug and unplug it. you can feel a clip on top, press down then pull the plug.

4. Get the plug out of way, get use the E8 trox with extnsion to reach the small trox screw. Need to be very patient to wriggle back and forth, can't see, only feel. and the flex head is very loose, so you have to use finger to support it to the right position.

5. I found one Hand can't get the job done, so I dismantle the last black block( use star head to unscrew the center of the black squre block ==last one) on the engine to ACCESS from driver side. After loosen the trox screw, you have to reach it with finger to pull out with the wrench.

6. pull out the bad CPS, notice the up side (which the screw hole always down side ).

7. Put the new CPS in, then screw on the Trox. use3-4 layer of thin tissue paper into the trox head then you won't loose the crew, then stick the screw with the wrench into the hole to tight it ( it plastic, don't over tight)

8. Plug in the plug. then restore everything else in revers order.

And you are done. Car drives smooth like butter ( just kidding). and stupid wife won't complaining dare not to turn the air conditioner on because of sudden death of stupid German technology which scaled several layers of skins on my hands and arms.

I intend to post some picture but i need to find a sponsor site

pcy

I also searched for DIY instructions about how to replace CPS on M272 engine. I didn't find...

Here is the picture of the rear view of the engine (looking from the firewall). Is this the CPS location (red arrow)?

You referred to 'last black block'. Is it same as the item circled in the second picture?

I am assuming that you removed the MAF and the plastic tubing between the MAF and the throttlebody.

TruTaing

When I had my shop do this, it looked like a complete pain in the ___ to do. He did it in 15 minutes working only by feel from the top of the motor from the driver side of the MAF. I believe the w203 amg section has a DIY thread with several photos.

Nice job completing this on your own.

I have a feeling this thread will be more frequently visited once the photos are posted and all of the higher mileage m112s run into this issue. This item fails all too often w/ higher mileage m112s. I also posted some info on how to 'test' if this sensor has failed in my thread also.

zebra100

Your engine is quite different from W203. The red arrow in the first is right the black block on the second is not. Actually is the white smaller blocks on the right (driver side). Your CPS should also be on the right side which your circle is in the middle should not be right.

C230 Sport Coup

Glad to hear the autohauz CPS worked.
I've had a spare sitting in the glove, just in case for several years now.

Does the engine turn over when the CPS is bad?
Or does the computer see lack of signal or something, and then no juice to the starter?

My car isn't turning over, but voltage is fine, and all dash lights are on.
Ran yesterday, today it doesn't.

rushgary

I'm glad I found this forum, just replaced my Crank Sensor. This picture on this forum helped me find it, getting it out was another story, took me like 3 days. Mercedes wanted $450, I purchased the part for $150 & save a bundle on labor.

pcy

$150 for CPS? You've been robbed. CPS is around $40.

rushgary

Yeah I found that out two days after purchasing it from a Mercdes dealer. Live & learn I suppose.

C5C32

Hi guys. I'm experiencing this same problem now. Looking to buy a CPS. Just wondering if this is the correct part.

http://www.autohausaz.com/search/pro...rk%20%20Sensor

nothinnicetho

Total pain in the a** but saved a lot of money by doing it myself. Took me about 3 hours. Bought the CPS from Oreillys/Kragens for $60 out the door. Second hardest part was locating the CPS even with all the pictures online. Once you remove the MASF, there is a wire harness under that and I thought that was the CPS. It's not. CPS is more to the right of the block and down lower. Definitely need a bright flash light and a small mirror to find the CPS. The hardest part was removing the torx screw. That part took the longest and required the most patience. I used 1/4" socket. You must find the correct wrench assembly and extension, because you need a proper/good angle to unscrew the torx screw. Once you get that off, it's all downhill from there. If you plan on DIY, then the main thing you will need is the right tools, a lot of patience, and a good amount of time. Make sure you have plenty of daylight and some bright flash lights. Also, the engine needs to be cool. Don't try to change the CPS after you drove your car. Then you will need a big sleeping bag to lay across the engine because that is where you will be laying for a couple hours and you want it to be comfortable. Do a lot of research in these forums and get a tool list and get directions with pictures of what you are doing. Print them out and have them with you. That's what I did. Tips: after you get the new CPS in and you are ready to put the torx screw back, tie fishing string to it in case it drops. Then you will not lose your screw. To make it stay in the wrench you are using, stick toilet paper in the wrench head and then put the screw in. It will stay in place and you will have fishing string tied to the screw just in case it falls out. An extra person with you also helps. I almost quit so many times. Was even looking on CL for mobile mechanics. I'm glad I stuck with it tho. Saved a ton of money. Hope this helps. Car is running great now with out stalling!

nothinnicetho

That doesn't look like the right part. It should be crankshaft position sensor. you are on the right website tho. I saw someone post it somewhere in one of these forums.

nothinnicetho

It should look like this...

http://www.autohausaz.com/search/pro...ition%20Sensor

C5C32

Great! Thanks so much for the quick response guys. I'm going to attempt this DIY later this morning. Wish me luck. If I'm understanding correctly, it almost sounds like the job is much easier to do from underneath, with the car up on a ramp or jack stands.

kirax2

WOW NOW I FEEL SO MUCH RELIEVE NOW!! SO ITS THE CPS!! FINALLY I STFF and i read so many post it is finally it was the CPS, ok part only cost 50bux, now i will just need to find a shop that can do it! and to the OP, i can't agree with you more, i just recently move the Vegas and yes the heat is horrible... i guess that's how the problem caused..

OldSchoolC240

Having just done the CPS replacement on my 2003 C240 wagon, I thought I’d share my experience for those of you who will be taking this on. In the spirit of giving back to the community that has saved me thousands of dollars and given me the confidence to dive into some pretty complex repairs, I've compiled some notes.
I used the search function here at MBWorld to find what I needed to take this job on. I did find some ambiguities though so, I’ve committed my notes to the attached PDF. I used pictures that I gleaned through searching and I did take the picture of the tools with my phone.
Through the proper and exhaustive use of the search tool here, you’ll find most of the pictures you'll need. I would suggest searching on “MAF removal”, “Crankshaft Position Sensor” and “Air Filter removal” for photos.
All directions are for my M112.916 engine, from my memory and are provided for your entertainment and not as an official repair instruction. All pictures are the property of their owners and used here for illustrative/educational purposes.

woodshc

Does the new CPS need to be re-initialized by a Mercedes dealer?

nothinnicetho

no

J.Christian

I just bought one New on eBay for 18.99 delivered... They have more.

Jamie

vert

Did the cheap ebay CPS work out for you? Considering buying one as well.

woodshc

Yes, it worked just fine.

vert

OK, I bought a new one from ebay for $11 shipped and hopefully it will work.

Ahmer

I TOO WAS ABLE TO DO THIS IN 1 hour...

USE A 1/4 in. drive! I had to buy another socket for my 1/4" otherwise you cannot get the darn screw to come out!

MINE WAS 18 bucks from WBAY as well!

vert

Just finished this...

The biggest mistake I made was trying to get the torx screw out with just an extension. MAKE SURE you have the flex head on your 6" plus 3" bar. Also, I did not disconnect any vacuum hoses. The only things that needed to come off on my c320 were: engine cover, MAF and its wiring connector. Laying on the engine, left hand fingers were on the bolt and right hand with the extension, flex head and socket went to the right of the wiring harness where the CPS wire goes. Left hand was deep down, while right hand was in line with the the top of the engine. Basically your left hand is just there for guiding the extension, grabbing it and putting it on the torx screw. Once the screw is loose, your right hand is not doing anything and your left hand is finishing to unscrew the torx screw and palming it.

To put the screw back in, I stuffed a small paper towel piece AND also used a small piece of DUCT tape to connect the flex head with the side of the torx screw. Once the screw is threading correctly, you can yank the flex head off the torx screw, take the tape off and finish screwing it in.

vert

Now the car is shaking/stalling when coming to a stop or giving it gas from a stop. Once it is at speed, no problems. I checked the vacuum hoses and do not see anything disconnected. Took the MAF off and looked around and everything seems OK, but it certainly sounds like the problem described in the PDF document attached. Best way to trobleshoot this? Start spraying carb cleaner when the car is running to listen for increase in engine RPM's? I must have detached something while laying on the engine replacing the CPS. No check engine light and no stored codes at this point.

vert

I don't see any lines that are not in their place. The sputtering comes back after driving the car for a while, when the engine is hot and only at close to idle speed. It is similar to how it was acting with a bad CPS but without any stored codes/CEL now. When I replaced the CPS on my BMW I had to have the dealer reset it before it started working fine. Everyone says you don't have to reset it on the Benz, but I do have the Carsoft - is there a way to reset it from there? I tried erasing the adaptation values with Carsoft, but that did not help.