DEF range low

[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.