Hi folks,

I just bought a used 2015 GLK250 and the engine light went on after a couple of days driving it. Drag! My Code Reader says it's a P242D (sensor 3) which means it's an Exhaust Gas Temperature issue.

From a little poking around I sense this might be a common problem on GLK250s.

Does anyone know of this issue? And what is the underlying source? And is the cure expensive? And is it safe to drive while I'm waiting for it to be serviced?

Any info would be much appreciated.

Thanks!

Chad

 

Welcome, and at the same time, sorry for your troubles. The Bluetec system is notoriously difficult to properly diagnose, especially without MB-specific code readers or scan tools.

That could very well be the EGT sensor, or it could be any other of the dozen sensors in the emissions system; even MB dealers seem to have a hard time identifying the right item which results in costly repairs that sometimes don't fix the actual issue (part of the reason these cars get a bad rep).

While the engine won't be harmed if you drive it around for a while as you go about diagnosing and trying to get to the root of the problem, I wouldn't ignore it either. Sooner or later it will trigger other faults in the system, perhaps interfering with the DPF cleaning cycles and you may end up with a cascading effect. Better to root it out now and fix the underlying problem.

I would make sure I had a MB-specific scan tool, diagnose the right sensor, replace if defective and clear codes. Then see how it does. Good luck and post back.

 

Hi andreigbs,

Thanks for the info. Very helpful!

My Code Reader is an Autel Autolink AL319. It can read MBs but is it too generic? Should I buy an MB specific Reader?

Also, to everyone - When you get the P242D (sensor 3) Exhaust Gas Temperature warning, does it generally mean one particuar problem or problems?
I'm concerned about taking the GLK into the dealer and getting charged for everything under the sun until they figure it out.

Again, thank you andreigbs! I feel like I got free advise from an expert!

Chad

 

get the icarsoft MB2 on amazon. It is specific for Mercedes and can read the proper codes. Generic readers are useless with our emission system.

 

Hey C300fan2,

Just ordered one. Thanks for the advice! I'll update the thread when I use it.

Is anyone else familiar with this kind of sensor problem?

Chad

 

Definitely NOT an expert, but I've learned plenty by making my own mistakes as well as learning from others.

I second the advice for the iCarSoft for MB. In terms of MB dealership service, if you have a good relationship with one it might be an option to have them diagnose it and perhaps fix it, but the chances are it will be expensive due to the labor charge. I'd much rather not visit the stealership if I can fix something myself, so I'd try it out first. There are plenty of Bluetec owners on this board who have dealt with various emissions issues, so a thorough search of this subsection would be worth your while.

 

Hey andreigbs,

Thanks for more good advice! I'm pretty handy but not with cars. So I'm going to take my chances with the stealership. Very Peter Tosh! I'm glad I posted. It's always good to be informed.

Thanks so much!

Chad

If anyone else has had this issue it would good to hear about it.

 

When you get it, you can update the firmware online from their website to have the most current software.

 

Good tip! I'll definitely do an update when it arrives. Thanks!

 

Bought the Icarsoft Code Reader and it gave me the same reading as the Autel. Went to a MB garage and they told me to go to the dealership because the dealership has better computers. The garage did however NOT charge me (nice guys) and gave me their readout which was more specific.

The readout said:
1. Soot content found in the DPF.
2. Outlet system temperature sensor 3 is short circuiting
3. Charge movement flap is faulty
(I've included a pic)

Any ideas would be appreciated. Thanks in advance!

Chad

 

Your DPF must not be able to complete a regen, or if it has, there's still soot in it above the threshold. This should resolve once the faulty sensor is replaced and a full regen takes place.

The charge movement flap error sounds like a mechanical fault in the air intake, either in/near the throttle body or on the manifold itself. These flaps are operated either electronically or by vacuum, and if the flap doesn't close/open it will set a hard fault.

What was the exact code for that last one?

 

Hey andreigbs,

I don't have the error code. (it wasn't included in the pix) Good news! I took the GLK to the MB dealer and they are going to replace 2 temperature sensors and the DPF for free. Wow. I got lucky on this one.

I do have to thank you andreigbs because much of the info you provided helped me have an informed discussion with the dealer guy. And I think it resulted in him being cooler about what the problem is and cutting me some slack in terms of the price.

When I get the GLK back I'll post exactly what was replaced and what they think caused it.

Thanks again!

Chad

 

Sounds like you scored a big deal. Those DPFs aren't cheap! The sensors alone are hundreds each, so I'd say you really lucked out.

Post back with the results of the fix and what all they replaced. Part numbers would be helpful, especially those sensors. I hope I don't have to go through the same ordeal later...

 

Hi folks,

My engine light story seems to be continuing.

I had two temperature sensors replaced and the engine light went away. Great!

But after a week the engine light came back on!

The code is P2002 and it says - Diesel Particulate Filter efficiency below threshold bank 1.

Does this mean I have to replace the filter? The dealer rep said once the sensors were replaced they indicated the filter was in good condition. Maybe that was a false indication and now the system sees that the filter has in fact failed?

Any ideas would be appreciated.

Thanks,

Chad

 

If the DPF was really replaced it should not be clogged so soon. Remember that in the US your major emissions components like the DPF are covered by the EPA mandated 8 yr/8k mile warranty and the dealer should fix them for free.

 

^ Agreed. If they replaced the DPF and the sensors, you should be covered by the dealership's 12k mile/1 yr warranty on repairs they did as well. Take it back to them and let them know the issue is persisting despite their swapping parts out.

BTW, this is a perfect example of dealers throwing parts at the car (expensive parts outside warranty!) and the customer ends up with the same problem a week or two later, along with a now-empty wallet or full credit card. That's how the Bluetec's get their bad rep.

Take it back to them to fix until the problem is correctly addressed. They should be eating the cost of diagnosis and parts since it's all emissions related and part of what they worked on previously.

Good luck.

How many miles on it btw? Any service history you can look up? You could try the free MyCarFax app.

 

Thanks formerjeepguy. In a few minutes I'm going to respond to you your original post. (FYI MB has NOT replaced my DPF)

 

Hi formerjeepguy and andreigbs,

Just to be clear - MB only replaced the temperature sensors. MB has NOT replaced the DPF yet...that might be next.

Thank you for your original post formerjeepguy.
QUOTE: "Your DPF may need a good regeneration cycle to burn the soot to ash or it may be full/blocked. DPF and emissions problems could be the reason the previous owner bailed on that car, but I digress. If the DPF just needs a good regen cycle you can try driving it at highway speed 65+ mph for 30 minutes and if that doesn't get it your DPF may need to be cleaned. There are many shops that specialize in DPF cleaning now that every modern diesel has to have one.

However, the DPF should be covered by the EPA mandated 8 year/80k miles emissions system warranty and if you fall into that category then your local dealer should fix it for free."

I'm going to get on the highway later and see if I can get a regen going.

Do you guys think if that doesn't work then simply replacing the DPF would be the answer?

Also, I'm going to the cottage in a couple of weekends. 4 hours there and 4 hours back. Is that a bad idea? OR Maybe it would be good for the filter to burn the soot out?

Thanks so much both of you for your help!

Chad

 

I think the differential pressure sensor detects the DPF load and that could be giving a false positive. The DPF can be cleaned or replaced - the dealer may opt to just get it cleaned. Cleaning means sending it out to a specialty shop and takes a couple days minimum. They flush them out and bake them in an oven.

I wouldn't take a trip 4 hours from home until it is fixed, but you have to decide that for yourself.

 

Thanks formerjeepguy. I'm going to take your advice and not go on a 4 hour drive till fixed.

 

Hey andreigbs,

You wanted to know the part numbers for the sensors. I'm attaching the work order info. To be quite honest I'm not quite sure which number applies to the sensors so maybe you can figure it out from this pix. BTW the sensors were covered by the 8 year warranty. Yay!




The GLK has 43,000 miles on it.

I'm taking the GLK in tomorrow to probably get a new DPF which the rep says will be free (parts and labor).

That's about it. My only curiosity is if I can go on a 4 hour drive to the country and 4 hours back with the car in this state. Formerjeepguy says best not to.

Thanks for all the awesome info dude! I appreciate it.

Chad