kenjraustin

Hey Folks,

Just thought I'd document my experience for others who happen to have a GLK Bluetec.

I have a 2014 GLK 250 Bluetec with 47k miles on it. The car ran beautifully for years - really right up until about 44k miles when the CEL came on. I bought a OBD2 and was able to get a cryptic code that I couldn't figure anything out from. I tried clearing it but it pretty much immediately came back on. In TX we don't have to do emissions as a part of the state inspection - so it's safety only. I didn't know that as this is the first diesel I've owned so when I took it to get inspected at one of the 15 minute chain places they told me it was going to fail because the CEL was on. So, long story short...

I took it to a local shop that specializes in BMW/Mercedes and they isolated it down to the DPF and knock sensors. Their estimate just for those 2 was almost $4400 for parts and labor. The guy called me from the shop and let me know that when he tried to order the parts from his vendor - my VIN came up and the parts shop suggested that they tell me to take it to the dealer because there's some kind of 8/80 emissions warranty and they should cover the DPF filter - but probably not anything else. What was strange to me was they were charging me over $1k for knock sensors when I can find them (there are 2 for this engine) for around $50 each. I know they are a PITA to install because the entire intake manifold needs to come off - but I watched a guy on YouTube get it off in probably 20 minutes or so, tops. So, even then it should cost a few hundred more bucks for labor at the shop, I would think - not thousands.

Anyway, I talked to the shop foreman over my MB dealer where I bought the car and we chatted for about a half hour on the subject. Basically, he told me, "all cars have issues...this is the issue with this one...".

So, right now it's at the dealer and I'm going to pay the $150 diagnostic fee (which the shop foreman said was actually a good deal because they have to do all kinds of work to figure out the DPF and whatever else might be in error because of that...).

I'll post back later with more details when I get them but I've seen a few folks on the forums here talking about these cars and this issue in particular. It appears as though it's the Achilles heel for this particular car/engine.

I haven't had any performance issues, I'm certain the car isn't knocking so I'm not terribly worried about the knock sensors. I drove 20 city miles to the dealer this morning and the trip computer showed 33mpg so I don't seem to have any performance issues with the car. I'm not saying that ignoring the issue for the long term is the right solution, but if they'll replace the DPF filter and perhaps the knock sensors (if that was the correct diagnosis from my local shop) then maybe I'll go from there.

I think I'm going to try using this stuff: to see if that mitigates the issue. Who knows - better than doing nothing. My wife is the primary driver of this car and if we get it fixed and the error code goes away I'm going to make sure that she only uses Shell, Valero or other high-end gas - not 7/11 or the grocery store or wherever she has been going up until now.

Who knows if that will make it any better but again, better than just doing nothing. If I didn't have 4 payments left and just put new Michelin tires ($1k) and a new brake/rotor job all around (that was only around $300 since I did all the work myself), I'd probably contemplate just selling it if I could get the error code to go away.

But, I bought this car with the intention to run it into the ground so even if I can't get the CEL light off and I can still pass state inspection then maybe I'll just drive the **** out of it until it dies and cut my losses. I'd take it in the shorts selling it with the CEL light on with this issue and I'm sure I'd get jacked on a trade-in from the dealer with them even knowing that they have an emissions lemon. I wondered why they quit selling the Bluetec's the year after this - and I guess now I know why. The service tech told me that the gov't told them to quit making them...not sure the details behind that but not a good sign.

I'll keep the thread posted as I learn more.

GLK Super Fan

If u need a new dpf, i can sell u mine. Just PM me for more details

andreigbs

Sorry to hear of your troubles with the DPF and associated sensors. I believe they are actually NOx sensors and not "knock" sensors, but that's a minor point.

The issue is that with some BlueTecs there was a rash of bad NOx sensors or they may just fail prematurely. This affects the emissions system, which includes the DPF, and that probably triggered the CEL.

Now, the emissions system warranty DOES last longer than the powertrain or "new car" warranties, so be sure to exhaust (no pun intended) that avenue first before handing out your own hard-earned cash.

Your options include having the NOx sensors replaced (if truly faulty) and having the DPF cleaned (big rig truck repair shops do this) or replaced, or you could just delete the entire system and get updated engine management software to complete the process.

Driving it as is won't hurt the engine, but it will potentially further clog or otherwise damage the DPF.

kenjraustin

I might be a buyer depending on what they say. Right now it seems they'll replace it for free under the 8/80 - it's the NOX sensors that they won't. I thought the quote from my shop was wrong - no idea how the KNOCK sensors would crap out because of emissions... And, the price makes more sense.

I just wanted to start a thread on my experience for posterity for others who come into the forum to see if others are having similar issues.

How big of a deal is the DPF delete process? You think a shop would do that? I'm pretty handy and did all the work on a 87 Porsche 944 turbo I had a few years back - but I watched a few YT videos and getting stuff in this 250 looks like a total German PITA. The DPF is buried under all kinds of stuff in the engine bay - be quite a pain to get it out and these days I just don't have the time for my car to be down like that - send the DPF for cleaning, reinstall, etc...

andreigbs

A fellow member has documented his process (at a shop, in Canada) and it could probably be done at home by the advanced DIYer with appropriate tools and patience. Linky: https://mbworld.org/forums/glk-class...-disabled.html

The software part you'd have to get done by a pro.

If it was me I'd probably buy the NOx sensor(s) myself and replace. I wouldn't trust a shop that can't even name the right part or give you part numbers for reference. Replacement sensors have held up reliably from what I've read here. They can be found here and cost about $420.

I doubt I'd let them do the DPF, as if it's covered by the 8/80, then the dealership should also do it for free.

In any event, good luck with your situation. Don't feel like you have to get taken for a ride. While the system is important, it shouldn't destroy the engine (the REALLY important bit).

kenjraustin

So, not suprisingly - the dealer came up with a different diagnosis. They said the DPF and the AdBlue Preheater assembly needed to be replaced. The DPF was under the 8/80 but the preheater wasn't and quoted me around $5k + tax to replace the heater. I went looking around and was able to find the entire preheater assembly for around $1100. Other things I read said this should be no more than 3 hours of labor - so have no idea where they are coming up with the $5k price tag for this fix.

This really pisses me off to no end. A vehicle that's been dealer maintained and has 47k miles on it subject to over $8k of emissions repairs after 4 years of service? What the actual $%*&?

I saw a couple things about AdBlue/NOX/DPF delete kits and am tempted to just go down this route. I don't know if I have the time or patience to do the install myself - curious if a local shop would perform those - probably not due to liability, etc... who knows?

The thing that gets me about the preheater is that I live in Texas - the car has never been out of Texas and the way I understand the preheater is that it doesn't even funciton if not in extreme cold temps to begin with. So, the fact that this thing doesn't work now is insane.

What I'm most worried about of course would be spending the $ to get this fixed, driving away and 300 miles later the CEL comes back on and I bring it back in and now it's the NOX sensors or who knows what else and it's thousands of dollars more for the fix.

At this point I'm tempted to just leave it as it is. It clearly doesn't affect the cars performance. I'm still getting 33-35mpg and the car runs as well as it did when I drove it off the lot 4 years ago. I guess if I don't do the delete anytime soon I can take it to a shop and see if any other error codes are coming up since I won't be able to tell because the CEL will remain on in perpetuity so I won't be able to see if anything 'new' is happening.

andreigbs

We don't call them "stealerships" for nothing. You can be sure labor rates are exorbitant, and that they don't quote you parts prices from other manufacturers other than OE. With the various supplies, fittings, gaskets, etc., you can expect that kind of quote.

I'd like to know how they determined the preheater is faulty. I'd also like to know how a (presumably) faulty preheater directly affected the DPF. In other words, I don't think they're related.

If I were you, I'd tell them to just do the DPF replacement for free and that I'll take my chances with the preheater. Dealers are known to throw multiple high-$$$ parts at a problem even if not always needed. Get what you can for free with the 8/80 warranty and run away.

I would also look for a more robust code reader. I've been using the BlueDriver thingy from Lemur and I can tell you it's been an excellent little device. It can display all sorts of emissions and exhaust system info, among many other systems as well. $100 well-spent, IMO.

formerjeepguy

My DPF clogged up at 18K miles and threads like this make me glad that I bailed on that car when I did.

The codes for the DPF are pretty specific so its hard to understand how the two places came up with different diagnosis. I would be tempted to take it to another dealer and have them check it out without telling them what I think it is to see what they come up with.

The DPF can be cleaned and there are companies that do it for big trucks all the time. They will happily clean yours too. Just find out for sure what the problem is first.

kenjraustin

yeah i guarantee you could take it to 5 different places and they'd all tell you something different. As others have mentioned it seems like the shops just throw parts at this because they don't really know what all gets jacked up. The service guy told me a lot of times they won't see all the error codes until other parts get fixed. So, the DPF gets fixed and I drive it out and 300 miles later the CEL comes back on because the NOX sensors are jacked. They'd happily take another $2k from me to fix that...and on and on...

As someone else posted previously, I'm going to have them fix the DPF since it's under warranty and then take it to the other dealer and see if they diagnose it the same. Only thing is - MB charges us $150 to hook our cars up and tell us what's wrong with them. I might just buy the dongle tool that was mentioned previously and see if that gives me any info as to what's going on.

As I said up front, if I wasn't a few payments away from owning this thing (and got a great deal on it brand new through the USAA buying service) and just put $1300 in it for new tires and brakes/rotors - I might bail on it too. But, with the CEL I'm gonna take it in the shorts re-selling it to someone unless they know the drill and are willing to do a delete or something. Most people would just freak out and low ball or run, and I can't blame them. I'm just going to drive it into the ground - let my kid drive it later or whatever. The engine actually runs perfect - great gas mileage and other than this debacle this is the very first issue we've had with the car. If the pre-heater is really the issue I'll either figure out a way to delete it in the future or just live with it. I live in Texas - it shouldn't even be used for about 360 days a year - no idea what temp it kicks in - but down here I'd imagine not all that often, if ever. Thankfully, I don't need it pass any emissions for a state inspection here - just the safety portion so at least there's that...

kenjraustin

alright so final post on this for now...

the dealer didn't actually diagnose a DPF fault. Their diagnosis was only the AdBlue preheater and because there seemed to some fill sensor that was faulty as well they apparently thought they needed to replace the entire tank to the tune of over $5k. They wanted 6 hours of labor to remove and reinstall the AdBlue tank. Insanity.

So because Im able to pass the safety test and no emissions test in Texas I just passed. Even the service consultant said he would be interested in a final 3rd party diagnosis to see what they came up with. I'd be happy to do that except everyone obviously wants $$ to do that - usually around $150 just to hook it up and test and I already paid $150 to the first shop. Miraculously, MB didn't charge me the $150 fee - they only charged me the $7 fee for the diesel safety inspection.

So, as it is now - that's where I'm going to leave it. $5k to replace the entire AdBlue tank is completely asanine to me and it's clearly not impacting the drive ability of the vehicle. I'm still getting over 30mpg in city driving with this thing. Not only that, the car runs great.

I only have a few more payments and just put over $1300 in the car for tires and brakes so I'm just going to drive it into the ground. I'll probably hook it up from time to time to see if there are any other fault codes that popup.

bugelrex

this post should strike fear in any GLK250 owner

Wonder what the % of failure is amongst long term GLK250 owners? I doubt its high enough for a class action

karmikan

Came across a highly instructive video by John Cadogan, an Australian mechanical engineer. He addresses the diesel vs gas issues and particularly the DPF problem. The video is more than 20 mins long but he's pretty entertaining and it's not just dry science. He starts touching the DPF stuff around 9 mins into the vid but the nitty gritty comes in about 14 mins until 17 mins. Spoiler - The key to everything seems to be cleaning the DPF by highway driving on a regular basis. City driving a diesel is the kiss of death for the DPF and he blames car dealerships for not instructing buyers.

andreigbs

@kenjraustin
In case you decide you want to tackle this issue yourself, there is a "repair kit" that MB sells (here) that should solve your AdBlue temp sensor and associated CEL issues. With the onset of winter soon, it may be a good idea and something an indie MB tech might be able to do as well, if you decide it's just not something you want to tackle yourself.

107123210

I have had my 2014 GLK250 for 5 years now and have not experienced any emissions problems.

I did know about the NOx sensor problem back in 2013 not long after I purchased the car. We were about to leave on a long trip and I was very concerned about the CEL light and message limiting car to 10 starts. I contacted MBCanada. They were not responsive to me, but when I took car into dealer, they must have had instruction from MBCanada to address my problem Regardless, never had a CEL light in 5 years. About 50k km at present.

The DPF must be a known problem given that they have now extended the warranty on it to 10 years.

It's such a great car - or would be in areas where the built in chemical exhaust processing plant could be eliminated!

andreigbs

That "10 starts remaining" message is not a defect, problem, or failure. It's simply information letting you know the DEF fluid level is low and that you need to add more. The tank holds 7.5 gallons and should last you a full oil change interval, if not more.

a64armt

107123210

You should go back and read the early threads about the 10 start message. It is not only to do with the DEF level. It had a lot to do with defective NOx sensors in early cars and likely other things as well. Some owners were not able to get there cars back for months, after they took car into dealer.

andreigbs

I did just that, quite a while ago in fact.

What I meant was that on a normally operating vehicle, seeing that message is normal and expected if you don't keep the DEF filled properly.

I don't dispute that other sensors go bad sometimes and, in turn, cause this message to appear erroneously. But that's not the intended cause for that message. In those cases, the proper repairs may be difficult to complete if the stealership doesn't know what to look for. Hence the months' delay.

And just to remind folks: unless you're under warranty or you have an excellent relationship with your local MB dealer, there's no good reason to go there and overpay. Use an Indie, or do most things yourself. Stealerships are notorious for using the wrong spec oils in Bluetecs (and TDIs for that matter), and sometimes break things that were fine previously.

kajtek1

Well... that's the story I will follow very carefully.
I placed order for DPF for 2014 E250 and the part turn out obsolete.
7 months after dealer took my money, the part never left Germany.
Let's see what is going to happen here.
EDIT.
that reply belongs to topic about E250.
The forum script glued this topic to the one I was reading and my reply was directed to different planet.
I complained about idiot who made the program year ago and still waiting for administration to take care about it.

smk1

Kenjraustin, what was the final solution/how did it fair?

2015 GLK250... 44,450 miles.
Like, Kenjraustin, no issues up until now.
CEL won't stay off.
Dealer did something/replaced something with emission sensor; CEL came back on.
I took it back to dealer, they don't know what's up now... said my battery is on the weaker side (I have never had any battery issues, or even a delay in turning over the key) or a fuel injector wire has slight rodent damage. They re-set the CEL.
It comes back on sooner/as soon as the computer re-sets so I cannot pass my SMOG test (I'm in CA).

mono4lamar

SMK1,

What are the CEL's?

What part of CA are you in? I have a very good scan tool and I'm currently chasing a similar problem. .

smk1

I am in Los Angeles.
The codes are P24C600 and P24C762
Where have you gotten with it, if anywhere?

Joseph~

P24C600 may be the dpf pressure differential sensor

A reference;
M-B Fault Error Codes/Diagnostic Trouble Codes (DTC)
See URL:
https://w220.ee/M-B_Fault_Error_Code...ble_Codes_(DTC)

If you are told it is the DPF, send it out to be cleaned{they bake it at very high temperature for a long tine] cost around $400.00 last time I looked.

See DPF Regeneration

https://www.dpfregeneration.com/

Regards

Joseph~