DEF Gauge Issues, questions.

[Josh W]

I just broke 2000 miles on my new silverado 3500 duramax. After towing on are rally cold, -15f degree day def gauge read 30%. I know it was full when bought. Dealer went to top it off and it only took .25 gal. Long story short it reset itself after 3 days and dropping to 29%. Today I towed and the low I saw was -18 F. Gauge is reading at 30% again and I know its wrong. Is this a common issue? If its cold related could it be a bad sensor? Will replacing it fix it? I will really be upset if it causes speed to be limited when def is not actually low. One day it was -20 and truck had sat for over 24 hrs and wouldnt start. I plugged it in and it started a few hours later. It kind of sucks having to open the hood to plug it in. Dealer said gm does it on purpose so the plug doesnt get covered in dirt/ice. Any solutions for this? My friend has a gmc 3500 and it's run through the grill. Thanks in advance. I am stoked on the power of this truck but concerned as its having a few glitches and is brand new.

[Colossus]

The DEF is frozen so yes those readings are common that you are seeing. Go say hi over at duramaxforum.com and post the issue over there as well, you'll get confirmation and a lot more info and knowledge over there as well, not a ton of new diesel owners over here, just us older folks.

[Chevor]

How familiar are you with diesels?

 

I have seen the percent issue. Happens when DEF is frozen, dont worry about it unless the truck derates.

 

No start issue usually meanss not enough antigel additive in the fuel.

[Josh W]

Thanks you guys. Sounds common and not too alarming. I am new to diesels so still have a lot to learn. I'll check out the other forum. Thanks again.

[revrnd]

Kind of off topic but a friend of mine in an over the road truck driver in northern Ontario. I think it was 3 years ago when he got a new Peterbilt which was the 1st truck he'd driven that req'd DEF. Well on a trip around the north side of Lake Superior the DEF system craps out & derates. I think rather than wait on the side of the highway in colder weather than what the OP was seeing, he limped about 50 miles into Thunder Bay Ontario.

 

That wasn't the only issue he had w/ the truck that winter which was colder than the average he'd been seeing. He was pretty ticked off about it considering his previous truck, a Navistar didn't cause him any troubles during the winter months. He figured Peterbilt did their cold weather testing in Denton TX. I was a bit puzzled. He said that was their HQ.

[newdude]

DEF is 67% water so it is susceptible to freezing. Per GM, DEF freezes at 12 degrees Fahrenheit/ -11 degrees Celsius. I'd garner to say that the urea content is what lowers the freezing point of it.

 

Some info on DEF from GM:

 

General Information

Note: DEF usage will vary depending on: driving style, trailer towing, loaded vehicle weight, weather, idle time, PTO usage.

 

As a general rule, when the DIC shows a DEF level of anything except OK, you can add at least 2.5 gallons (9.5L). The amount to add to top off will vary.

Diesel Exhaust Fluid (DEF) is required to maintain normal vehicle operation and emissions compliance. When filling the DEF tank, there may be a short delay before detecting the increased level of fluid and updating the Driver Information Center (DIC).

 

Diesel Exhaust Fluid (DEF) has a shelf life of 2 years. However, this can be reduced if the fluid is exposed to direct sunlight or above 30°C (86°F) for sustained periods. All DEF packaging should be labeled with a production date.

 

The Driver Information Center (DIC) will display a series of messages regarding the amount of DEF that is available. When mileage countdown is zero, the vehicle speed is reduced. Refer to Owners Manual.

Cold Weather Operation Information

DEF freezes when exposed to temperatures below -11°C (12°F). In cold conditions it is normal for DEF to freeze. The tank and delivery lines are heated to thaw frozen DEF. When filling the tank in cold conditions, the vehicle may not recognize the new level until the tank thaws. In certain cold conditions, it is possible to find some frozen DEF in the DEF fill pipe opening. If you are expecting to be in extremely cold areas, it is recommenced to fill the tank prior to cold temperature exposure.

 

Edited December 30, 2016 by 15HDriver

[Cowpie]

Yeah, frozen DEF. Only problem with that till it thaws thru the system is that more EGR is used to counter NOx. And with the colder engine temps until thoroughly warmed up, that could lead to more DPF regen cycles. What a mad, mad world.

[PaddyO]

2016 - 2500 Silverado with 2400 miles on it - 57 hours on the motor...While trailering a 29' - aluminum 4 place snowmobile trailer from Pittsburg NH to Saguenay Quebec in 28F weather the cluster reads DEF level is @ 30%. Not a big deal, pull over and top off the fluid. 150 miles later & 2 -3 on off engine cycles the DEF gauge still does not register full but had dropped to 28%.

 

Fortunately Arnold Chevrolet is located next to the hotel in Saguenay. After dropping the trailer I drop in unannounced hoping they tell me to turn the key and press the pedal a # of times and it will reset. NOT ! The service writer informs me it doesn't work that way. A technician was required to reset the gauge by means of computer. I am told that was the only way. A 1/2 hour labor for a total $ 65CAD + - and my gauge has been reset and I am out the door. The service manager told me to claim the $ with my dealer when I return to the states. I'm happy as ARNOLD Chevrolet dealt with my issue immediately with no messing around as it was near closing time when I stopped in. I only hope the DEF gauge continues to read "OK" on the way home as we have a lot of hills to pull in not so so nice weather conditions during the 310 mile one way trip trip and can't afford this beast to go into limp mode because of a faulty DEF reading.

 

Wish me well on the return trip....

Edited January 17, 2017 by PaddyO

[Ted S]

2015 Silverado 2500HD High Country Duramax 6.6L.  The DIC for DEF reads 30% and I added 2.5 gallons a few days ago.  Temperature has been below 20ºF to -12ºF for several days.  Today got up to 25ºF.  I assumed the DEF froze and hoped it would thaw with heaters, especially now with warmer temps, but it has not.  I'm supposed to start a trip to Arizona from Twin Cities, MN tomorrow towing about 6,000 pounds.  Is this too much risk, hoping the DEF sensors will thaw and I'll be OK?