KrustyKustom

Anyone know if you can purchase individual components in the AdBlue tank? I have a Fault code of 203D17 (which says Fill Level "AdBlue" short circuit to positive). I think the issue may be in the level sending unit or the sub harness at the tank. In the DAS it gives some resistance levels for the various levels of the tank which I will check as well however I was looking in EPC and only see the tank listed as a unit. I also see in EPC a tank heater repair kit?

Anyone been down this road yet?

The SCR/NOx simulator is looking pretty good as well!!

alx

Individual pieces like heater, level sensor, pump are not available. However a new canister is available- it includes a new heater and a new level sensor.

Btw, level sensors rarely go bad- there are no moving parts. It is your harness - either the trunk connector or the level sensor connector... What does burn often is the heater though.

KrustyKustom

Alx, thanks for the input.

I am going to drop the AdBlue tank and check out the little harness that is on the tank itself. The DAS shows the resistance values range so i will check that out as well.

Much rather fix a connector or the little sub harness than the whole dang tank!
I cant really complain though, I have not had any emission related issues in 94k aside from two NoX sensors.

alx

Yes- four long bolts hold the tank. Easy to drop. Be careful as it will be somewhat heavy especially if it full. Check harness for continuity. One end terminates on the pump assembly, the other at the SCR controller in the trunk cheek pass side.

fireman1073

i bought a heater off eBay around 600$
not sure about other parts

alx

you bought the whole canister which includes the heater and the level sensor.

KrustyKustom

So an update to my post 5 months ago. I dropped the AdBlue tank ad went through the wiring diagram in DAS of the tank sub harness. The actual wires came back as fine but I was still getting a short to positive code. With 102k on the truck I decided to replace the tan assembly.

Got the new tank in, put in 2.5 gallons of DEF and cranked er up. In DAS I did the actuations and pump tests and everything is working right but the pump is not building pressure. It shows pressure at 38hPa , keeping DAS hooked up and driving it around it has not called for dosage yet but the DEF injector does pass the click test. Does the pump line need to be disconnected and primed? Surely my brand new OEM pump is not underperforming?

Anyone dealt with this?

alx

Stop driving immediately if you dont want to burn out the new pump. The pump needs to be primed before installation. This is not listed anywhere, but is a requirement. You need to fill the canister with def before you insert it in the tank. You also want to remove the hose from the pump outlet and fill up the outlet with def.

See here my warning on this a while ago:

https://mbworld.org/forums/gl-class-...ml#post6523642

KrustyKustom

I am dropping the tank now! luckily i have a transmission jack that makes lowering that heavy DEF tank easy.

After I fill the housing and test with DAS i will post an update.

thanks Alx!

KrustyKustom

I have had success! After reading Alx's post about priming the AdBlue pump I went back at it. When I changed the tank out (with pump/heater) I initially charged it with 2.5 gallons of DEF. I went down and picked up two more boxes and added 5 more gallons which was about up to the neck. Then in the DAS software I was seeing the pump would not generate any pressure. After reading Alx's post I went and looked closely at the tank assembly I took out to see how it was made in the center canister and where the holes were. There is a whole series of holes at the top of the canister so I figured what the heck, let me try and fill the tank to the brim and see if it will prime. I tried but it would not, I ran the test about 4 times and no pressure would build. Then I got an idea before dropping the tank again, why not bounce the back end and see if it has a bubble or something in the pump chamber. I put a hitch in the receiver and while the test was initiated to run the pump I went back and jumped on the hitch bouncing the rear of the GL. Sure enough! it went from 69 hPa to 5000 hPa! Wahoo...

Ran the test in DAS again and the blue pressure line on the graph is supposed to cross the two red ones twice, it worked perfect!

For my weekend that started out with my two college daughters home saying "why is Dad in the garage all day" to having a successful repair weekend. I also changed out the rear air bags while I had the rear end up high. On my truck both rear mufflers/tailpipes have to come off to get the AdBlue tank out so I am glad that it worked out.

Thanks to all that contribute constructively to the forum. I really enjoy working on my vehicles (I have 4 MB), and not sure what I saved doing this myself dollar wise but I really enjoyed learning more about the truck.

alx

Lol @ jumping on the hitch... but if it worked... hey...

Callisto1

About 10 days before Thanksgiving, I started the GL350 on a 75 degree morning, and the CEL came on. I plugged in iCarSoft reader, and it was the Adblue heater. So I cleared the fault, and drove the rest of the day. Several times, the vehicle sat for an hour or more between starts. No new CEL.
Next morning (another in 70s) CEL is back on. Again I clear it, and drive the day without incident. I do not drive it everyday, and not at all for 6 days around Thanksgiving, but when I do, the first start of the day shows CEL. I clear the fault, and it never returns that day.
So can I do this indefinitely, knowing 10C/50F is the coldest morning the vehicle has EVER seen in the 6 years I've owned it? Yes, it's a 2 minute PITA every morning to clear the fault, but that's better than $$$ and hassle to replace the heater & tank.
And what happens if I don't reset the fault? Does engine eventually go into limp mode?
FWIW, the dealer replaced the original tank about 4 years ago because of heater fault code, under warranty.

alx

What is the annual sticker inspection procedure? If they read the obd2 port you will not pass. The diesel requires anywhere between 100 and 400 miles for all obd2 monitors to become “ready” after a check engine light reset...

Callisto1

Florida has no inspection requirements.
But I am not trying to disable or bypass the DEF system. Just the heater, which seems superfluous in a zone 10 tropucal climate.

alexasoto

I have a 2013 GLK 250 with a Fault code 203D17. Trying to buy the def heater module with level sensor and I wonder if the correct part number 2044710575?