ARE YOU ABSOLUTELY CERTAIN THE DEALER FILLED UP THE DEF TANK? BY THAT I MEAN, DID YOU ACTUALLY WATCH THEM DO IT?

WHILE YOU'RE CONSIDERING THAT, MAY I SUGGEST YOU LOOK TO THE LEFT SIDE OF YOUR KEYBOARD AND FIND AND PRESS THE "CAPS LOCK" KEY?

Thanks.

 

I have a new to me 18 and the dealer did not fill mine. I got to the 800 miles left mark and put 4 gallons in and I reseat my trip a to see how long it takes to get back to 800 miles left.

 

As others eluded to, I’d top it off and then see what’s what before getting too worked up. It’s an easily missed and screwed up item at the dealership. In fact mine was supposedly filled once, and soon after my windshield washer jets clogged up with some weird crystallized stuff. Guess what that was. They wouldn’t admit it of course. Fixed it though.

Also, as a heads up, towing this things drinks DEF. Not towing, you may see that 5000. Just topped mine off after 3500 miles not towing anything with 2.5 gallons.


Sent from my iPhone using Tapatalk

 

I would also check and ensure all recalls are up to date. There was a recall for reprogramming the ECM that impacted the regen cycle periodicity. Most found that their trucks did regens less often after the reprogramming.

 

But regens have nothing to do with DEF.

 

The DEF thing on these are ridiculous. However, I usually get well over 7500 per refill. I personally will never trust these dealerships and do my own checking for recalls. There was a recall this summer for ECM programming I believe.


Sent from my iPhone using Tapatalk

 

Nope, JD is correct. DEF and regen are separate systems. More fuel you use more DEF you use so if you have a lead foot ........

 

Dealer probably did not fill up the DEF tank.

Like Sambor said ... DEF usage is directly proportional to fuel usage ... i.e. the more fuel you use the more DEF you will consume.

DEF consumption will be approximately 2% of the diesel fuel consumed.

Another way to think of it ... DEF is consumed on a 50 to 1 ratio with diesel fuel.

Your DEF tank holds 7 gallons.

7 gallons x 50 (50:1 ratio) = 350 gallons of diesel / 36 gallon tank = ~ 9.7 tanks of diesel fuel

350 gallons of diesel x 15 miles per gallon = 5,250 miles (on 7 gallons of DEF)

350 gallons of diesel x 10 miles per gallon (towing) = 3,500 miles (on 7 gallons of DEF)

But if your truck displays a reminder when you only have 1,000 miles before the DEF tank is empty (and truck speed is significantly reduced) ... then you would only get 2,500 to 4,250 miles on a full tank of DEF before you would see the 1,000 miles remaining warning.

Remember ... the EPA controls federal policy on vehicle emission control standards ... so GM simply sets the DEF dosage rates to the allowable NOx emission control standards.