Check Engine Problem
11-08-2008, 05:40 PM
#26
Super Moderator
Glyn & Amanonfire: Thank you! I just checked my cam sensors, one was ok, but the other had oil in it! Wow, would have never thought to check these! I literally had my CEL come on Wednesday night, and have hardly driven the car since then. So I figure I will order the cam sensors and pigtails and install these myself. Right? I figure the sensors can't be too hard to install...Also, I'm still thinking of getting a warranty and then eventually claiming my A/C blower regulator on that since its not such a priority with winter coming and all... Any advice on the warranty? Who to go with?
The sensors (magnet assemblies) are easy to replace. Get the right tools - disassemble & reassemble the same way. Tie up the pigtails well so they can't get in the pulleys & the poly V belt. Take off the piece of harness between the leaking sensor & the ECU which I seem to remember is to the right rear of the air cleaner. Clean up the harness thoroughly with electrical switch cleaner & reinstall. If you can't get it cleaned up properly, replace it. You dont want oil creaping around the ECU system. I've never stripped a 4 banger but have watched a friend for moral support. If another member wants to step in with better detail please do. Hope this cures your problems - Good Luck
11-08-2008, 06:58 PM
#27
Super Member
Thanks Glyn, luckily there is hardly any oil in the connector as of now. The car will not be driven until I fix this, so I should be ok. I checked the wiring, and there is no oil anywhere outside of the one faulty sensor and the attached connector.
11-08-2008, 07:22 PM
#28
Super Moderator
Hey! That's good news. When it gets bad it will cost you an engine bay wiring harness
11-10-2008, 11:23 AM
#29
Unless you got under the car and checked the O2 sensor connectors (drivers side, beside the oil drain plug) you haven't checked all the connectors.
Pull the rear ECU connector and run your finger along the contacts, don't be so sure there's no oil. $6 of electrical contact cleaner will go a long way to not replacing a $350 engine harness.
The cam sensors were $50 CND each, and the isolation cables $40 CND each. Replace 1 cam sensor, yet buy TWO isolation cables incase the other cam sensor starts leaking.
Clean the O2 sensor connectors several times with electrical contact cleaner. There will e tons of oil in them, and if you're lucky, they'll work after cleaning.
So $50 + 2x$40 + $6 == $136 and you're done, plus a day of cleaning electrical connectors.
11-10-2008, 12:31 PM
#30
Super Member
I already ordered two cam sensors (figure it's better to replace both than have another go out on me sometime soon). I also ordered both pigtails from the dealer today, so hopefully by Wednesday I should have the car running again. As I had stated I checked both cam sensor and only one had a miniscule amount of oil, so I figure I caught the problem early enough. As far as the O2 sensors go, I will check those later. Are these sensors prone to leaks as well? If so, we have some S#!TTY hardware on these cars! 
How do I go about checking these sensors? Do I just unplug them? Thanks for your help. Oh and one more question: When I replace the cam sensors, if that is the only issue, will the CEL turn off automatically or do I need to get it erased by an OBD computer?
PS. Anybody know what size and type the bolts on the cam sensor housing are? Need to buy the proper socket...
How do I go about checking these sensors? Do I just unplug them? Thanks for your help. Oh and one more question: When I replace the cam sensors, if that is the only issue, will the CEL turn off automatically or do I need to get it erased by an OBD computer?PS. Anybody know what size and type the bolts on the cam sensor housing are? Need to buy the proper socket...
Last edited by dbvolz; 11-10-2008 at 12:34 PM.
11-10-2008, 12:39 PM
#31
Super Moderator
11-10-2008, 12:45 PM
#32
Super Moderator
11-10-2008, 12:56 PM
#33
MBWorld Fanatic!
There's a DIY around here somewhere.
They had this problem on the M111 and used the same 271 pn pigtail.
I got lucky, a dealer decided to do it for me under warranty!
I kept wonder what the pn described as "magnet" was....and then I saw one of the extensive articles on this subject and found out what it was.
As far a proper tools, any work you do on a benz requires
a. a set of torx bits
b. a set of inverted torx bits.
c. a set of metric sockets
and less frequently
d. a set of metric allen heads.
Invest in the whole sets it's cheaper that way.
Most auto parts stores have the set of torx and and inverted torx.
Or you can get them from Craftsmen.
They had this problem on the M111 and used the same 271 pn pigtail.
I got lucky, a dealer decided to do it for me under warranty!
I kept wonder what the pn described as "magnet" was....and then I saw one of the extensive articles on this subject and found out what it was.
As far a proper tools, any work you do on a benz requires
a. a set of torx bits
b. a set of inverted torx bits.
c. a set of metric sockets
and less frequently
d. a set of metric allen heads.
Invest in the whole sets it's cheaper that way.
Most auto parts stores have the set of torx and and inverted torx.
Or you can get them from Craftsmen.
I already ordered two cam sensors (figure it's better to replace both than have another go out on me sometime soon). I also ordered both pigtails from the dealer today, so hopefully by Wednesday I should have the car running again. As I had stated I checked both cam sensor and only one had a miniscule amount of oil, so I figure I caught the problem early enough. As far as the O2 sensors go, I will check those later. Are these sensors prone to leaks as well? If so, we have some S#!TTY hardware on these cars! How do I go about checking these sensors? Do I just unplug them? Thanks for your help. Oh and one more question: When I replace the cam sensors, if that is the only issue, will the CEL turn off automatically or do I need to get it erased by an OBD computer?
PS. Anybody know what size and type the bolts on the cam sensor housing are? Need to buy the proper socket...
How do I go about checking these sensors? Do I just unplug them? Thanks for your help. Oh and one more question: When I replace the cam sensors, if that is the only issue, will the CEL turn off automatically or do I need to get it erased by an OBD computer?PS. Anybody know what size and type the bolts on the cam sensor housing are? Need to buy the proper socket...
11-10-2008, 02:17 PM
#34
Super Member
There's a DIY around here somewhere.
They had this problem on the M111 and used the same 271 pn pigtail.
I got lucky, a dealer decided to do it for me under warranty!
I kept wonder what the pn described as "magnet" was....and then I saw one of the extensive articles on this subject and found out what it was.
As far a proper tools, any work you do on a benz requires
a. a set of torx bits
b. a set of inverted torx bits.
c. a set of metric sockets
and less frequently
d. a set of metric allen heads.
Invest in the whole sets it's cheaper that way.
Most auto parts stores have the set of torx and and inverted torx.
Or you can get them from Craftsmen.
They had this problem on the M111 and used the same 271 pn pigtail.
I got lucky, a dealer decided to do it for me under warranty!
I kept wonder what the pn described as "magnet" was....and then I saw one of the extensive articles on this subject and found out what it was.
As far a proper tools, any work you do on a benz requires
a. a set of torx bits
b. a set of inverted torx bits.
c. a set of metric sockets
and less frequently
d. a set of metric allen heads.
Invest in the whole sets it's cheaper that way.
Most auto parts stores have the set of torx and and inverted torx.
Or you can get them from Craftsmen.
No! the oil works it's way down the wiring harness from the cam sensors & they get dirty. - Just uplug & clean - look for signs of oil.
11-10-2008, 03:04 PM
#36
Unless you got under the car, took off the belly pan, then you haven't checked the O2 sensors.
If you clean them, and they start working well again, the CEL will reset itself. Its a good check to see if cleaning worked, otherwise you need new O2 sensors.
There won't be a "lot" of oil in the connectors, cause it leaks into the harness. So while they may look OK, don't bet against how much oil has leaked. I had removed the ECU a few times before someone posted the cam sensor leak info and then I checked and finally noticed the oil - that's how little there was.
Have you ever gotten a "low oil level" message? This is another indication.
When you order the cam sensors, make sure you order the plug that goes in the middle. Mine came without it, and I foolishly installed it myself not realising there was a hole in the middle leaking oil and sucking up dirt.
11-10-2008, 03:07 PM
#37
Just check the cam sensors for the isolation cable, if they are installed, then great, if not, GO GET THEM cause these cam sensors leak, all of them, there is no updated part #.
Its a common problem on a LOT of MB models, just the design of the wire harness on the M271 causes oil to leak to the O2 sensors. Better than the M111 where oil would leak into the ECU!
The dealership in my town replaced 6, yes SIX, O2 sensors on a friend's car before I diagnoses the oil leak for him. That means the mechanics changed 6 oil soaked O2 sensor connectors without thinking there was a problem.
Dumb dumb dumb.
Its a common problem on a LOT of MB models, just the design of the wire harness on the M271 causes oil to leak to the O2 sensors. Better than the M111 where oil would leak into the ECU!
The dealership in my town replaced 6, yes SIX, O2 sensors on a friend's car before I diagnoses the oil leak for him. That means the mechanics changed 6 oil soaked O2 sensor connectors without thinking there was a problem.
Dumb dumb dumb.
11-10-2008, 07:39 PM
#38
Super Member
"Checked the wires"?
Unless you got under the car, took off the belly pan, then you haven't checked the O2 sensors.
If you clean them, and they start working well again, the CEL will reset itself. Its a good check to see if cleaning worked, otherwise you need new O2 sensors.
There won't be a "lot" of oil in the connectors, cause it leaks into the harness. So while they may look OK, don't bet against how much oil has leaked. I had removed the ECU a few times before someone posted the cam sensor leak info and then I checked and finally noticed the oil - that's how little there was.
Have you ever gotten a "low oil level" message? This is another indication.
When you order the cam sensors, make sure you order the plug that goes in the middle. Mine came without it, and I foolishly installed it myself not realising there was a hole in the middle leaking oil and sucking up dirt.
Unless you got under the car, took off the belly pan, then you haven't checked the O2 sensors.
If you clean them, and they start working well again, the CEL will reset itself. Its a good check to see if cleaning worked, otherwise you need new O2 sensors.
There won't be a "lot" of oil in the connectors, cause it leaks into the harness. So while they may look OK, don't bet against how much oil has leaked. I had removed the ECU a few times before someone posted the cam sensor leak info and then I checked and finally noticed the oil - that's how little there was.
Have you ever gotten a "low oil level" message? This is another indication.
When you order the cam sensors, make sure you order the plug that goes in the middle. Mine came without it, and I foolishly installed it myself not realising there was a hole in the middle leaking oil and sucking up dirt.
11-11-2008, 03:24 AM
#39
Super Moderator
Just check the cam sensors for the isolation cable, if they are installed, then great, if not, GO GET THEM cause these cam sensors leak, all of them, there is no updated part #.
Its a common problem on a LOT of MB models, just the design of the wire harness on the M271 causes oil to leak to the O2 sensors. Better than the M111 where oil would leak into the ECU!
The dealership in my town replaced 6, yes SIX, O2 sensors on a friend's car before I diagnoses the oil leak for him. That means the mechanics changed 6 oil soaked O2 sensor connectors without thinking there was a problem.
Dumb dumb dumb.
Its a common problem on a LOT of MB models, just the design of the wire harness on the M271 causes oil to leak to the O2 sensors. Better than the M111 where oil would leak into the ECU!
The dealership in my town replaced 6, yes SIX, O2 sensors on a friend's car before I diagnoses the oil leak for him. That means the mechanics changed 6 oil soaked O2 sensor connectors without thinking there was a problem.
Dumb dumb dumb.
11-11-2008, 04:26 PM
#40
Super Member
Update: The isolation wires are arriving at the stealership tomorrow, and the cam sensors should be coming tomorrow as well. I picked up a set of Torx sockets and some contact cleaner. If everything goes as planned and it really is just the cam sensors that are causing the CEL, then I should be done with this tomorrow! I will post pics from the fix, stay tuned. BTW does anybody have any ideas for getting the car up off the ground? I only have the factory jack, and was thinking of driving the car onto some bricks or something... Any ideas?
11-11-2008, 05:08 PM
#42
Super Member
11-11-2008, 05:33 PM
#43
Super Moderator
11-12-2008, 11:28 AM
#44
I suspect you've been leaking oil for a long time now. Pull off the belly pan under the engine and I'll bet you $5 its coated in oil.
11-12-2008, 03:45 PM
#45
Super Member
These engines do not burn or leak oil. I asked the dealer about my first low oil message and they said it was "normal", only to discover the leaking cam sensors later.
I suspect you've been leaking oil for a long time now. Pull off the belly pan under the engine and I'll bet you $5 its coated in oil.
I suspect you've been leaking oil for a long time now. Pull off the belly pan under the engine and I'll bet you $5 its coated in oil.
The tech didn't mention any oil or anything. Either way I'm dropping the car off tomorrow at the shop to get an estimate (that way I know exactly what I need to fix). I'm keeping my fingers crossed it's just the cam sensors and pigtails that I need...
there will be other distractions
11-12-2008, 11:25 PM
#46
Junior Member
Join Date: Jul 2008
Location: Kenilworth, Cape Town, South Africa
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'04 C 200 Kompressor
Our consumer watchdog in South Africa got hold of this issue and splashed it all over the press as a time bomb waiting to go off - MBSA says there has been a running change in production of these sensors & that QC has been tightened up with the supplier - No new part number but I have to say that the incidence of trouble has reduced drastically and seems thusfar restricted to older production vehicles. I do not know of a single case of a W204 with this engine having trouble - time will tell
Looks like my bomb is done ticking... also got a MIL / CEL about 2 days ago and went away soon after but back again... wonder if it is the CAM SENSORS or PCV problem cause I did notice a slight surge in the revs while at idle...
Wish me luck... gonna have to check it and spend some money... well at least the car is still under warranty/motorplan but I will still have to pay 50% of the cost
11-13-2008, 11:23 AM
#47
The techs that looked at my car changed the O2 sensors that were DRIPPING oil, don't expect a tech to tell you if the belly pan is coated in oil, they don't care.
11-13-2008, 07:00 PM
#48
Super Member
OK so we were all wrong. Apparently the cam sensor is leaking and not bad enough to trip the CEL. This is BECAUSE.... my vacuum pump is leaking oil. Also, my vacuum hose is leaking. I will be replacing the cam sensors regardless, as well as adding the pigtails. Not the good news I was hoping for... 
11-14-2008, 12:40 PM
#49
OK so we were all wrong. Apparently the cam sensor is leaking and not bad enough to trip the CEL. This is BECAUSE.... my vacuum pump is leaking oil. Also, my vacuum hose is leaking. I will be replacing the cam sensors regardless, as well as adding the pigtails. Not the good news I was hoping for...
11-14-2008, 04:25 PM
#50
Super Member
Not only did they charge me $98 for the diagnostic (at least I got to drive the new C class loaner), but they also gave me a nice size estimate:
Fix Vacuum Hose Leak - $802
Fix oil leak at Vacuum Pump - $509
and I was having problems with my A/C blower
Blower Motor Regulator - $436
the independent told me this could just be fixed by replacing the dirty A/C filter, something that SHOULD have been covered in Service B.
All I can say to this:
There is no way I am getting my car serviced at MB Sarasota again. Luckily I found a reliable independent MB tech who will take care of the problem Tuesday. He's gonna run a diagnostic and let me know the exact problem since I can't trust MB Sarasota apparently. Oh, and my buddy broke my passenger door pull ($44 part), got quoted $368 for that. I replaced it myself in 20 minutes...
