2014 159" Diesel 52,000 miles. Wondering if anyone has ever had this happen: The DEF Low Refill Soon message appeared, but the tank is full. My mechanic (not a dealer shop) is able to imitate the sensor with the scan tool so we are pretty sure it not an electrical issue. Could the tank level sensor be fouled with crystals? Trying to avoid the 2k for a new tank. Thanks in advance.
DEF Low light on, DEF tank full - need advice
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The crystals (Urea) in DEF is very soluble so if liquid is in the tank above the sensor it is doubtful that is the issue.
I would try emptying the tank, removing it, Rinsing it with distilled water and perhaps some soap a few times and reinstalling it. It is hard to believe the sensor is part of the tank and requires a full tank replacement but I understand it does. Any chance of getting the sensor from Europe? It may be just as fine to run with the light on and see if you ever get to the countdown. If you don’t then top up the tank every 4000 miles and drive on.
Look at this thread as it was the wiring not the sensor or tank:
www.promasterforum.com
I would try emptying the tank, removing it, Rinsing it with distilled water and perhaps some soap a few times and reinstalling it. It is hard to believe the sensor is part of the tank and requires a full tank replacement but I understand it does. Any chance of getting the sensor from Europe? It may be just as fine to run with the light on and see if you ever get to the countdown. If you don’t then top up the tank every 4000 miles and drive on.
Look at this thread as it was the wiring not the sensor or tank:
Well.... the love affair was short lived.... :)
Man it seems the diesels are having a rough go! I have been lucky with my gas but have run into some Business Link issues with getting a loaner while they have my Pm in for service. Best of luck on the service. Not to point fingers but the number of transmission and flex plate failures and a few...
www.promasterforum.com
Thanks for that link. My mechanic is going to drop the tank and clean it. That other thread also mentions corrosion of the wiring. Hopefully it's that. It truly is a horrible design, but I need to fix it as I am selling it (it's a fully built out camper). Cheers.
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If worst case try finding a salvage tank with the condition the sensor has to be good or money back!
Def level is a 14 position reed switch get a rubber mallet and bang the tank near where the sensor pack is about where the wires go into the tank. I have also read it being an optical switch, but they should all be in one module pack inside the tank.
2016 136WB low roof diesel, converted to an RV by Sportsmobile, TX
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409 Posts
Not advice on how to deal with the problem now, but how to prevent it: don't put DEF in until the van tells you to, then only put in one jug of DEF (2.5 US gallons, usually). Unless you are driving hundreds of miles every day, you won't go through enough DEF to keep it from going bad if you fill the tank all the way.
The only exception would be if you know you will be going on a very long trip, and will burn through what you put in quickly.
I suppose you could try putting WARM (not HOT - if you wouldn't pour it over your unmentionables it's too hot) water in, waiting a bit, then sucking it back out with a siphon, to see if you have crystals built up that need to be dissolved. I haven't tried this, so take it with a grain of salt.
The only exception would be if you know you will be going on a very long trip, and will burn through what you put in quickly.
I suppose you could try putting WARM (not HOT - if you wouldn't pour it over your unmentionables it's too hot) water in, waiting a bit, then sucking it back out with a siphon, to see if you have crystals built up that need to be dissolved. I haven't tried this, so take it with a grain of salt.
So soaking the tank got the sensor working again, but the DEF low light is stuck on. Is there a reset procedure?
2016 136WB low roof diesel, converted to an RV by Sportsmobile, TX
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409 Posts
If things are working correctly, putting DEF in should clear the light. When you say "The sensor is working", what makes you say that if the light is on and the tank has DEF in it?
Def is in the tank and the sensor is signaling properly, the but the light remains on.
So after 700 miles, the light is still on, but the van drives amazing. Going to wait it out like in this post (seems to be the identical issue): DEF Refill soon
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