Hey all, just wondering if anyone has received this code on a GLK250.. It's a 2014 and has 73,000 miles, from my understanding this is the "reductant level circuit sensor high" error.. Something to do with the adblue tank, but I haven't seen a message to add def or any messages about limited starts.

Just looking for some ammo before I head into the shop where they'll tell me I need to replace the entire system or something ludicrous

I couldn't find anything on this forum specific to the GLK and this issue, but others have mentioned a re-calibration of the float in the tank or something to that degree with other MBs

Thank ahead of time

 

That's likely, given the way MB deals with anything emissions related. You're probably out of warranty, which means you are your own warranty. If you can, reset the CEL and see if it comes back.

If the AdBlue tank/components are starting to crap out, MB will want to replace the entire thing because it comes with the sensor and other gizmos inside. The "repair kit" is around $800 or so online. I can give you the link to MB OE parts site if you need.

What kind of commute does your Bluetec do? Just curious if short drives vs long freeway blasts may be a factor.

And good luck, keep us posted.

 

It went away on it's own for a week, then it came back. I reset the code but it came back a few hours later.. I'm also trying to find what all is covered under the federal emissions warranty as i'm still under 80k miles (by only 7k miles) My commute is half city and half highway, around Fort Lauderdale, so the highway traffic for the most part during rush hour doesn't give me ample time to get a long steady high speed drive to regen the DPF, but the code i'm getting isn't related to the DPF, or could it be? I was under the impression it's more to do with the tank or the tank sensor, but ultimately I do not know.

 

Unfortunately, I don't think it is covered under the federal emissions warranty. Certainly worth a try, but be prepared to be told "not applicable."

The "circuit high" code means there may be a disconnection of that component in the tank, and to check for any wire(s) that may have come out from their socket or is loose. If all looks good, the sensor inside the pump (which is inside the AdBlue tank) will likely need to be replaced. The unit itself is the AdBlue pre-heater. Don't know why it go bad in FL, though I've ready of another forum member from TX whose preheater sensor went wonky too.

As I said, since it's all inside the AdBlue tank, the dealer opts to replace the entire AdBlue tank assembly, including the pump that holds the sensor instead. I've read about estimates of $2-4k at MB stealerships. The part number for the repair kit is 204-471-05-75 and the place I found that sells it is an MB dealer site (link). If you want to be sure that's the faulty item, a trip to your local stealership may be required. Just be advised they will most likely charge you a diagnostics fee if you opt not to have them fix it. Usually they subtract that fee from the total when customers elect to have the repair done.

So plan your next actions carefully.

 

Thanks for your input, assuming the answer I get regarding the diagnostic is that I'll need to replace the unit, If i'm not receiving the "10 or 20 starts left" message; am I at risk of further damaging anything by continuing to use it? It sounds like a non-essential part for safe operation. Also, to check for a loose wire or a disconnect, am I looking inside the tank or would the connection in question be on the outside (top or bottom of tank)?

Thanks again for your input, i'm surprised at how common of an issue people say the adblue system is, yet I couldn't find a single reference to that code with a GLK 250

 

It may be a common issue with the Bluetecs, but the GLK250s are not at all common Most GLKs are gassers in the U.S., so the knowledge gap both among owners and repair techs is a concern.

As to your question: as long as the faulty sensor does not prevent the AdBlue from being utilized during regen cycles, there should be no damage. It may cause a permanent CEL until it's fixed, but I would scan it weekly and make sure no other codes are popping up as a result. Unless you need the CEL off so you can pass emissions inspections for registration renewal, I wouldn't worry about it. (As it is, that pre-heater is pretty much inconsequential south of the Mason-Dixon line )

As for checking the sensor wiring, that's probably a tricky exercise and not likely to be easy to access. The sensor is inside the pump, which is in the tank, which is in under the trunk essentially, so I'm not even sure what you'd have to remove to get at it. Most likely the tank drops from underneath, but I've never looked to find out.

 

I have not received any codes on 2014 GLK250 YET. But always interested in other's experiences.

This site gives same description as you gave, but not specifically for Mercedes. It does give some additional information:

https://www.autocodes.com/p203d.html

It could be that the high pin is not submerged and has crystals or other crud on it. Seeing it is the high sensor, maybe try filling with fresh DEF? I would try that and agitate it a bit. Maybe with an air hose.

Anything better than going to dealer

More good info here: https://www.obd-codes.com/p203d

 

Hey folks, I'm getting the same P203D. Ours is a '13. I doubt it is this simple, but back in Feb I put 5 gallons of DEF in (I got the x # of starts left message while on a road trip). I forgot I had and a couple of weeks ago I tried to put another 2.5 gallons in, and it overflowed almost immediately. I thought the tank was 7 gallons or so, so it doesn't make sense that the # of starts message came on, I put in 5 gallons, put another 2-3k miles on it, and then can't put any more in. Maybe I'm 'lucky' and overfilling it did it. Also, aren't there some wiring harnesses, etc. there as well? I'm wondering if some of the overfill might have corroded a connection. But that would be too easy.

What did you finally do to resolve it? Get the kit? Get a new tank? Take it to the dealer? Or did it stop on its own? I did smog 3-4 months ago, so I'm good for over a year and a half on the light. But I don't want to damage anything either.

What's included in that kit?

Appreciate any and all info, how it was resolved, etc.

Also, it's my wife's daily driver; plenty of around town driving. I used it once about every other weekend to pull my 3500# boat/trailer, but that is only 25 miles round trip (20 on the freeway). And I don't rev it up much; most of my shifts are between 1600 and 2000 rpm.

Thanks,

Gordno

 

Replies in red.

 

Quote: Also, it's my wife's daily driver; plenty of around town driving. I used it once about every other weekend to pull my 3500# boat/trailer, but that is only 25 miles round trip (20 on the freeway). And I don't rev it up much; most of my shifts are between 1600 and 2000 rpm.
FYI, turbodiesels love to rev and don't like to be *****footed around. Rule of thumb: when engine is cold, shift at 2500. When warm, shift around 3000. Getting on the boost helps retain cylinder pressure seal, among many other things. Don't be afraid to flog it now and then; it needs it.

I tend to shift between 1600 and 2000rpm when I'm pulling the trailer since peak torque is at 1600. I'm actually surprised that redline on this diesel is 5200. Maybe because I usually have it in economy mode (love 40mpg), if I mash it, I think it shifts around 4,000 (and sounds like it's going to blow up, although peak HP is at 3800). Don't think I've ever tried putting it in sport and flooring it to see what the shift RPM is. One of my part time jobs in college was driving an 18 wheel gas tanker. Good money for a student as long as you didn't burn up or blow up. Don't recall torque peak, but it had 13 gears and the shift band was something like 1600 to 1900 (300RPM torque band--yes, it had a turbo). Granted, a different animal from our GLK250 engine, but you sure noticed a drop off in torque if you went more than 50RPM over the torque range. But I'll do a little 'winding it up".

I'll check the connectors on the top of the tank first and then try to figure out how to drop the tank.

Thanks!

 

disregard this post.

 

Been there, done that, my friend. In a past life I was a long-haul OTR truck driver. In short, these 4-cyl twin-turbo DOHC diesels are not to be compared to the low revving class 8 behemoths. Having driven mostly diesels, I can report that they enjoy being worked hard and actually run the best that way. I don't mean red-lining them for every shift, I mean exercising them properly. Torque is probably the best thing about a diesel and the fact that it's available at humble rpms. But they do love to rev and they need it. I recommend at least using freeway on-ramps as a good place to take it up to 4000 rpms in several gears. Doing that daily will keep your turbos happy, oil consumption low, EGR valve clean and injectors spraying in the correct pattern.

Report back with your results of the adblue tank and connectors situation.

 

So, haven't found info on the bluedef tank yet although I heard that the tank should be drained and refilled yearly (never done it).

We just got back from a 1,200 mile road trip down to 29 Palms (an hour northeast of Palm Springs, CA). 500 mile drive the first day (3/4 of a tank... Average temp while driving during the day was around 100F. The P203D was previously on, I cleared it the night before before we left and it came right back on. My wife drove about 2/3 of the drive (I was working), Once we got there, we didn't drive it for three days so it sat in that heat. When I got in the car when we headed to Newport Beach, the check engine light was off. I don't know if it went off sometime during the original drive, or while it was baking for the following three days it sat. We were there for a day (cooler), and then I picked up a one-way rental trailer and we hauled a heavy sofa (sectional) back that my wife had ordered. Total weight of the trailer loaded was probably around 2200# (no big deal since I normally pull my 2500# boat. However, it was again in the low 100s (107 was the highest), and I had to drive over the grapevine (everyone in CA knows I5 grapevine). Absolutely no problems, and I drove around 70 in I5 in the central valley (3 hrs). Car performed flawlessly all the way home (25mpg with the trailer).

So, I'm wondering if the extreme heat somehow helped 'clean' the P203D. Or, was I getting that error message because I had overfilled the bluedef tank a couple of weeks before (I didn't get the P203D until after I overfilled it--maybe a few days) and the 500 mile drive dropped the level enough that it caused the error code to go away?

Also, the more I read about the emission system, it seems like I should change the oil at 5k miles instead of the recommended 10k miles due to the ERG valve, etc. resulting in more contaminates in the oil. I have always changed my oil on all my cars every 5k miles (once manufactures started recommending 7500 or so) since it is easy to look at the odometer to see if a change is needed soon. But I had decided to go with MB's recommendation of 10k (assuming the expensive oil we use is up to the requirements). Now I wonder if I should change to 5k to help keep the emission system a little cleaner.

Also, FYI, the highest the coolant temp got to was about 225F while charging up the grapevine with the trailer. During that same time, the engine oil temp got as high as around 252F. Am I to assume this is because of the turbos are being lubed/cooled by the engine oil? Most of the rest of the time engine oil was in the 220 range. Oddly, the tranny temp was initially the same as the coolant temp, but when the coolant went up to 225, the tranny temp was still under 200F.

 

I believe the turbos are oil-lubricated (and therefore passively cooled) which is why turbodiesels need high-quality synthetic oils that don't break down at the temps these turbos put out. And that was before they were made to get even hotter during repeated regen cycles. The oil is run through a coolant heat exchanger, under the oil filter canister. The transmission is quite robust, it just needs a drain/filter/refill every 60-80K miles if you want it to last a really long time.

Glad to hear your CEL went off; hope it stays off.

 

Has anyone followed up on the recent emission campaign for the replacement of pretty much the entire exhaust system? I brought mine in and had them replace everything, but came away with the same CEL code (P203D) my question is, will Mercedes replace the required parts for this fault? It's for a dad preheater if I remember correctly, but that part is not listed on the list of parts they'll replace. They will however replace the module, pump, etc as seen on the list. I'm wondering if this is one of those situations where the preheater is just a small part of a larger component (like maybe the module or pump?) which they would replace... hmmmm Bummer they didn't do a diagnostic while doing the repair, forcing me to return and gamble the $195 on whether it's part of the campaign or not..

 

You may want to subscribe to our dedicated thread on the MB Bluetec Settlement. There is a wealth of info there already, including photocopies of MB papers showing what parts will be covered under the extended warranty post-fix. The AdBlue system is listed in detail and will be covered for any faults found. This same info should be in the packet MB mailed you.