DEF range low

[24redDenali]

I got a message on my phone, but the truck showed almost full. I was able to add about 2.8 gallons before it overflowed. It still showed 1 bar down and error on app.

 

[pa31p]

Probably software update may fix this. never bothered with it but mine warns about 1000 miles out. little early I think too.

 

[RK58]

I had the software reprogrammed twice when I first got the vehicle and now it is acting exactly like yours. Filled mine went on a 2,000 mile trip and only reading 1 bar down, I knew it wasn't correct added 2.5 gallons of DEF when back home. I will live with the problem luckily DEF is readily available everywhere.

 

[Stbentoak]

Yes, these gages are a pretty inexacting science.. I pretty much just run mine till I get the thousand-mile warning, dump in 2.5, and keep motoring till the warning comes back.
This way, it's always fresh, I know I can go at least six to 10,000 miles before I get another warning, which is usually another year or so. 8 bucks at Walmart. It's really a no big deal.....

 

[JayceeP]

I encountered this issue about 2500miles into ownership while towing a jet ski and a loaded truck with wife, kid, dog, and gear for a 1-week cottage trip. I put one jug of DEF in before I left (about 250miles one way) and got this warning about 400 miles later when almost home. I finished the drive and once I got home I put nearly 2 jugs of DEF in before the tank over flowed (probably got 80% of the 2nd jug in). I drove for about 10-15 mins and finally all the warnings on the truck went away, first starting with the DEF low lock out screen and then that other range warning that comes up. Or, it might have been a check engine light. Either way, both resolved themselves with a little bit of driving however the app wouldn’t clear itself. I was about to head out on another 500 mile trip the following week so I booked it into the dealer. They did a software update and said all was good with the truck, sometimes the app just doesn’t jive.

By the sounds of it, as long as the truck warnings are gone, you shouldn’t have any system lock out issues with reduced speed regardless of what the apps says but I still don’t like that there’s these little demons happening.

3,500 miles later I haven’t had this issue since it happened back in early August. I’m somewhat inclined to see if it will take a jug of DEF fluid to see how much I’ve burned but I’ve seen other posters get much more range on a DEF tank if they aren’t towing. Most of my miles in the Yukon are highway and I only towed the jet ski once since August and that was 20 mins down the highway and back to get winter maintenance done in late October. Also had a few more miles on the ODO at that time so truck was probably performing more optimally too.

Edit- I think what happened is the dealer didn’t fill up my DEF tank before I drove it off the lot and probably had minimal DEF to begin with.

 

[Stbentoak]

I can't believe it would even know it was towing a Jet ski! I used to pull mine to the launch with my Polaris Ranger!
Something definitely wrong with it if you used that much....

 

[JayceeP]

I can't believe it would even know it was towing a Jet ski! I used to pull mine to the launch with my Polaris Ranger!
Something definitely wrong with it if you used that much....

lol… I forgot to add. I think what happened was the dealer didn’t top up the DEF tank before I took it off the lot in late April which is why I somehow “used” so much DEF in 2500 miles. I’m not sure what the factory adds for DEF but tank must have only been 1/4 full or something. But again, I did throw a jug in before the road trip and then added like 1.5-1.75 jugs after I got back 500 miles later and that’s when the def tank overflowed.

 

[Stbentoak]

I would say upon delivery... they are half full at maximum, or less....
I always stipulate on purchase agreement, Full tank of fuel and full tank of DEF upon delivery.

 

[JayceeP]

I would say upon delivery... they are half full at maximum, or less....
I always stipulate on purchase agreement, Full tank of fuel and full tank of DEF upon delivery.

Yeah I didn’t even think of it. New to owning a diesel. It was fresh off the truck…. Got them to put my 22” black wheels on, do the 10 year rust proofing treatment, and took delivery. Gas tank and windshield washer fluid tank was full at least lol

 

[TOP GEAR]

With my 24 Denali I often tow a 3500 lb trailer with a race car. Usually 400 to 600 miles one way. It will always start telling me on the way home that I'm about to run out and go into limp mode. If you stop and add def it might take 2 gallons. If you ignore it and let tell it's go into Limp mode, the screen tells you it is but never happens. On one trip last year I drove the rest of the way home, 250 miles then added 3 gallons. The dealer has been talking to GM about it. It clearly is bad software that they don't have a handle on. I had it to the dealer for 2 days and they are doing there best. this is a GM problem that is very frustrating for the customer. Other than that it's a great tow

 

[geobern]

My experience is that it takes the system some driving time to update. When I picked up mine at the dealer, it showed half full so I asked them to fill it up which they said they already did. They came with a tank to the lot to top off and it immediately overflowed the tank. They said that it would show full after some driving time, which it did.

 

[JayceeP]

With my 24 Denali I often tow a 3500 lb trailer with a race car. Usually 400 to 600 miles one way. It will always start telling me on the way home that I'm about to run out and go into limp mode. If you stop and add def it might take 2 gallons. If you ignore it and let tell it's go into Limp mode, the screen tells you it is but never happens. On one trip last year I drove the rest of the way home, 250 miles then added 3 gallons. The dealer has been talking to GM about it. It clearly is bad software that they don't have a handle on. I had it to the dealer for 2 days and they are doing there best. this is a GM problem that is very frustrating for the customer. Other than that it's a great tow

That’s good to know. So clearly towing messes up the range calculation (seems to be widely known) so the lingering question is if you have the warning despite having plenty of DEF, will you end up in limp mode? Sounds like no for you. Did you get a software update after this?

 

[Stbentoak]

Unable to Fill the DEF Tank – TechLink

gm-techlink.com

See if this helps....

 

[ducfan]

With my 24 Denali I often tow a 3500 lb trailer with a race car. Usually 400 to 600 miles one way. It will always start telling me on the way home that I'm about to run out and go into limp mode. If you stop and add def it might take 2 gallons. If you ignore it and let tell it's go into Limp mode, the screen tells you it is but never happens. On one trip last year I drove the rest of the way home, 250 miles then added 3 gallons. The dealer has been talking to GM about it. It clearly is bad software that they don't have a handle on. I had it to the dealer for 2 days and they are doing there best. this is a GM problem that is very frustrating for the customer. Other than that it's a great tow

This is worrisome. I have been reading various threads and watching Youtube videos on this very topic. Wondering why GM doesn't yet have a handle on software, warnings and def level while towing? I plan on ordering a Yukon with the LZ0 as soon as available in late March. The symptom I have run across is that owners add def on the road while towing, yet the warnings don't disappear and seem to get more ominous. What to do.

 

[UsualSuspect]

There is an update if you have the issue. My wife's Yukon has always worked like it should, my Sierra, out of the blue it stopped working and showed it was full all the time, software update fixed it. I am not sure why some have the issue, and others don't. Just my opinion, but GM should just update all of them while doing other updates.

 

[JayceeP]

Edit update: after about 20+ minutes of driving (after adding a 25 jug of DEF), the lock out range/speed warning screen disappeared. Toggled to the DEF gauge and have full bars. Still have the check engine light but if past experience is the same, the engine light should drop off soon.

Original post:
Just did a long weekend 1,200km/750 mile hockey tourney trip with the little guy. My def gauge was at 6/10 when I left town and 1/3 of the way in the trip I dropped one bar to half. Didn’t change since but as soon as I got off the highway exit to my house at the end of our trip, the Service DEF System/ 157km until 104kph max speed warning popped up.

I unloaded the truck and then stopped by the gas station and threw a jug off DEF in…. Drove for 7-8mins and went home.

Warning hasn’t disappeared yet. I may try to throw another jug in. Kind of annoying I didn’t get the X distance remaining warning and it just went straight to the lock out warning.

I probably had close to 8,000km/5,000miles on this tank of DEF.

 

[Stbentoak]

DEF should last you longer than that... I pretty much get 7k out of a 2.5 jug, and it holds over twice that much. I basically review my level every oil change and then decide if it needs one dumped it as part of that service routine. I've never seen the low-level warning in 4 years.

 

[JayceeP]

DEF should last you longer than that... I pretty much get 7k out of a 2.5 jug, and it holds over twice that much. I basically review my level every oil change and then decide if it needs one dumped it as part of that service routine. I've never seen the low-level warning in 4 years.

Yeah I agree. And it’s actually closer to 10,000km/6,000mi on that tank of DEF. I just checked my service history from August. I’m debating on getting a 2nd jug of DEF to see how empty the tank actually is but if I’m getting 10,000km I’m not too worried. I think I’ll just do what you do. If the gauge gets to half before my next maintenance, I’m going to throw a jug in and not think about it any more.

Side note: while I haven’t towed since I had this issue in the summer, I wonder how much highway speed and hills come into play. Nova Scotia isn’t mountainous but it is hilly, particularly the northern section where I definitely have some highway miles in.

 

[Stbentoak]

I don't think it means a whole lot as long as you're not towing. Hills and highway speed don't really stress this engine at all.....

 

[JayceeP]

I don't think it means a whole lot as long as you're not towing. Hills and highway speed don't really stress this engine at all.....

Yeah figured - though the drive home was pretty windy, rainy, and I was pushing the truck through the “mountains.”

Ah well. I’ll report back if anything else shakes out.