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2003 E55 2006 E320 cdi 2008 Ml320 cdi
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Discussion Starter #1
so i got a p0101 fault and was looking for some advice. The suv has 146k miles on it, the MAF is new due to breaking 3 months ago. new turbo and ccv vent tube seals. The turbo feels great, though i do have oil getting to it from the ccv valve which also has alot of damp oily dirt all over it and i can see its leaking down. I work 12 hour days and havnt had a day off yet to really tear into it so any advice before doing so is appreciated. when I had the maf off it looks like a oily layer inside of it which im suspecting to be causing the fauls on the maf sensors which happen to be a pita to clean. looks like ill have to remove the metal tabs holding them in to remove them and clean them.
If i clear the fault i can turn the suv on, drive it, drive it hard even as it feels great. the check engine light comes on when it is shut down and then restarted. its not going into limp mode and there are no other faults.
So I have see some info about a catch can mod, will this stop oil getting to the maf? also what causes the ccv to leak or fail?

Thanks for any info in advance. Josh
 

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2003 E55 2006 E320 cdi 2008 Ml320 cdi
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Discussion Starter #3
latest update, yes there are two mafs, they are in the single plastic T shaped plastic piece that feeds air to the turbo. The CCVV was pretty sorry so i installed a new one and also tried a new MAP sensor but apparently the car doesnt like Bosch as it threw a P0069 code for barometric presure and put the suv into limp mode. guess ill try a direct factory part this time. I cant find any air leaks anywhere. youd think with the oil rebreather going into the turbo the boosted side would have oil coming out if there was a leak somewhere as well. I did remove the MAF sensors and give them a good cleaning along with the sensor for the tube after the CCVV with no change. I have seen on the jeep boards alot of guys dont pay this one attention and the only one who posted a resolution was a new ecu =(
 

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2003 E55 2006 E320 cdi 2008 Ml320 cdi
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Discussion Starter #4
ANYBODY?? so i did some digging with sds today and the fault that is there, and will come right back without the engine even running is 2647-001 check component b2/7 right hot film mass air flow sensor. value is above limit.

I did the sensor check both without engine running and the running test and it checks out just fine. I also pulled the maf and swapped the sensors around and the fault stays the same so its not the maf. following the test with the engine running sds wanted to do a egr test which came back great. I cant find any wiring breakes which would make sence being the sds check gives out livestream data and its all in line. also why would i be able to clear it then immidiatly rescan before turning the car on and its back. Are there any MB techs out there that that have experience with this.

I did some looking on the jeep pages but most of them just ride with the check engine light but i cant stand it being on.

To do the EGR test sds wants the suv at 80c for oil temp and water temp, e brake in place and an ok Lambda value. the first test the value was at 5 which its supposed to be 5 to 7. the second time around it didnt want ot run the test and the lambda value was 0. while i was looking this up it magically came back to 5. I saw this has to do with the heater on the O2 sensor. does this have long cycles? if it was this it doenst seem to reason why i get the usual fault even with the engine off.
 

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2007 E320 Bluetec, 2008 320ML CDI
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I'm not familiar with the codes you've posted, but I had a similar problem on my '08 ML320 CDI.
I had removed one of the MAF's to look at it. Reinstalled it and I must have tripped something in it.
The SUV ran fine though the CEL was on. Mileage plummeted and I took it to the dealer.
The cure was a new 'Y' pipe along with new MAF's.
This was four years ago. All fine since.

Skippy
 

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2003 E55 2006 E320 cdi 2008 Ml320 cdi
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Discussion Starter #6
Thats why i swapped the two sensors around. what has me baffles is the diagnostics come out fine but when i clear it, and the engine isnt even running, ill rescan and there it is. i cant get rid of it at all. This is the only time in my life ive not been able to get to the root cause of a problem. Thanks for your reply my ears are open to anything.

odd though that your milage went down on the jeep pages i see guys unplugging the sensors saying they get better milage. Last week i pulled a 2007 bmw x5 home 3 1/2 hours with alot of hills and averaged right at 19mpg cruising 70-75.weight for suv and trailer probably about 7300lbs. I have to admitt that bimmer is a nice ride with more options, much much better seats but non of them have the cargo or tow capacity that the benz has.
 

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2008 ML 320 CDI
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15 Posts
Similar Experience; Advice?!?

Went on a roadtrip right after having the oil changed in my '08 ML 320 (has 113,000 miles on it); about 100 miles down the road, CEL came on; stopped, checked it, code PO101, MAF Sensor. Cleared it, drove it to destination , another 70 miles, CEL came on again. Came home next day, no issues, mileage OK, checked code again, same-same, cleared code, bot still have PO101 as a "Pending" code that won't clear. I agree that a lit CEL will drive you nuts, because you don't know if there if there is a new problem, or just the "Pending " one not clearing. Got under the hood, after doing due diligence with research on-line, had small amount of oil in MAF sensor assembly; got some MAF spray cleaner, BUT I can't seem to figure out how to remove the sensors from the housing duct boot. Cheapest replacement of the whole assembly, factory part, is $370; eBay has the sensors but I can't seem to find out how to replace them. I removed the metal retention clips, but the sensor itself only turns so far, and will not come loose from the air duct assembly. I live in an area of NC where I have to drive over 100 miles in ANY direction for a Mercedes dealer, so my local Ford dealer has been doing maintenance on this one, and a '01 ML 320 I had for 3 1/2 years before the gem I have now. I'm thinking the mechs might have overfilled a little on the oil change, getting oil in the MAF duct work that caused this, but in looking at some other threads, this is a problem that has popped up for other folks on a recurring basis. I'm reassured by the previous thread that replaced his whole assembly, and it has been fine for 4 years. My only concern is whether the on board electronics will reset after I spend $400 to put in a new MAF sensor assembly. Fortunately, replacing the whole part takes about 5 minutes. Any advice out there is greatly appreciated; I'll give my Benz Bro's a couple of days to let me know what you think. Thanks in advance.
 

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Coupe/Convertible Forums Moderator
CURRENT: 2011 SL550, 2011 C300 FORMER: ML350, CLK550 Cabriolet, C240, ML320, 300TD
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Don't buy critical parts on eBay or Amazon - even if you buy name brand Bosch or MBZ parts, there's a good chance they will be fake. Buy from a reputable automotive parts dealer such as Autohaus AZ, RM European, FCP Eruo, Pelican, etc.
 

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2008 ML 320 CDI
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Similar Experience; Advice?!?

Thanks for the advice; I ordered a new assembly from Parts Geek last night, OEM type, and I'll keep y'all posted. My code reader is "bare-bones" so I don't know what the more specific code is.

Bottom line, for my '08 CDI can I just change out the sensors without spending $380 for the whole assembly, IF I ever need another one? With my vehicle, I guess I'm at the point with it where some things may wear out, i.e., headlamps, turn signals, position lights. Thanks again for your help.
 

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2008 ML 320 CDI
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Closure for the PO101, but NOT for "Pending" code

Ok, Lads. Got the part from PartsGeek, Mercedes OEM, today, took me about 10 minutes to install. Cleared code other than "Pending", drove it 3 times, extended distance (40 miles0, vehicle is running great, mileage is an honest 25mpg. The only wrinkle (and I KNOW there are those out there that already know this) is that for a code that is "Pending", the Check Engine Light will not go off for at least 40 startups to warmup, and the Mass Airflow Sensor does not detect any more problems. THEN the CEL will stay off unless there is an engine problem. Very annoying, since trying to make sure there are NO OTHER problems besides the PO101. I'll post what happens; right now I'm at about 4 driving cycles, so it'll probably take at least 10 days.

2nd Thing; I documented the replacement of the MAF assembly with pictures, and the MAF sensors ARE removable for replacement or cleaning. Just remove the metal clips, top and bottom, and pull the sensors out of the assembly duct housing; they DO NOT come out easily, just be careful, and firmly pull. I'll post pictures of the evolution, for those that need the information. I kind of wish I had known more but I would actually rather have the new parts installed. Anyone who has a W164 3.0Ll CDI and needs an MAF assembly, email me, and I'll make you a great deal. Just remember that the parts are cleaned/refurbished.
 

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Sorry this took so long; I'm still dealing with the CEL coming on, but I got an ICarsoft V2 with MB software; turns out the code is just like the first post, 2647-1 (Component B2/7 Right Hot Film Air Mass air flow sensor). Took off the brand new unit (MAF Assy) cleaned all components with MAF spray cleaner, re-installed, cleared codes, test drove for an hour with no CEL lights; get home park it, re-start and the CEL pops on again. Honestly, for last 7 months, it runs great, my avg mileage is 25-26 mpg. The closest MB service is 2 hours in any direction, so I contacted an independent who has MB trained techs in Greenville, NC; I'll let you guys know it works out, but I have a sneaky suspicion it might trace back to either the EGR hose assy or CCVV.
 

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2008 ML 320 CDI
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Update from yesterday; Talked to a MB certified mechanic at an independent foreign car garage in Greenville NC with excellent credentials. Mech says they don't work on MB diesels because only the dealers have the software and diagnostics to fix this problem; he stated that the electronics are just too parameter sensitive for anything but an MB service center. Guess I'm looking at a 2 to 2 1/2 hr road trip to get this CEL issue taken care of. I DID look on the iCarsoft website, and they offer an OBD II scanner for MB that looks promising; I have the V2 2.0 scanner which is great, but not as comprehensive in the software department. Specs for the iCarsoft $299 model DOES state it will diagnose and clear ALL codes, including "Pending" codes. I'm still going to replace the EGR hose. Hope this helps anybody out there....
 

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02 ML320 06 ML500
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Update from yesterday; Talked to a MB certified mechanic at an independent foreign car garage in Greenville NC with excellent credentials. Mech says they don't work on MB diesels because only the dealers have the software and diagnostics to fix this problem; he stated that the electronics are just too parameter sensitive for anything but an MB service center. Guess I'm looking at a 2 to 2 1/2 hr road trip to get this CEL issue taken care of. I DID look on the iCarsoft website, and they offer an OBD II scanner for MB that looks promising; I have the V2 2.0 scanner which is great, but not as comprehensive in the software department. Specs for the iCarsoft $299 model DOES state it will diagnose and clear ALL codes, including "Pending" codes. I'm still going to replace the EGR hose. Hope this helps anybody out there....

Think about how and when this code was born. It was directly after the oil change.

And that requires the removal of the eng. cover. When reinstalling the eng. cover, it is imperative that the boot at the rear of the housing be correctly installed.

Please read highlighted items.
 

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Seriously!?! I'll get right on it, but Seriously!?! Amazing such a small thing could have such an impact on a finely engineered machine.As always, ATTENTION TO DETAIL. Thanks so much for the tip!
 

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02 ML320 06 ML500
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M/B has been living on the raves of their vehicles years ago. They dropped the ball on 272 engs. and all diesels.
 

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I appreciate the reference you gave, but mine (2008 CDI), doesn't have an air inlet in the engine cover; mine is through a grill in the hood directly to the air filter. I specifically wanted this model because it is an MB diesel; I had an '86 Isuzu Trooper 4 cyl turbo diesel for 11 years; lost it in a divorce, but I always said I'd get another one when I could. I really think it's not just MB; since the advent of on-board computers, the sophistication level of one small thing sometimes creates a domino effect for the whole system, but in my case, it's just the pain-in-the-ass CEL so far. Vehicle operates as it was designed to, mileage is the same, nothing unusual. I guess I'll have to bite the bullet and take it 2 hours away to a dealer; I really want to set this beast up to succeed, but not at an expense I'm not comfortable with. Thanks again
 
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