Heads Up 3.0L Owners. Def System Re Flash TSB

[ILSilverado]

Well I had the required re flash done for the DEF system and now she is drinking DEF like a $2 hooker drinks Ripple. I would say 50% more def consumption than before. Keep an eye on the DEF gauge folks.

[Sierra 3.0]

I can confirm.  I had mine done about 2200 miles ago.  I pulled a camper for the first time and, wow, it used a lot of def.  Now back to normal driving and it's still more than it was.  I'm guessing the update solved an emission issue with not running clean enough?

[ILSilverado]

9 hours ago, Sierra 3.0 said:

I can confirm.  I had mine done about 2200 miles ago.  I pulled a camper for the first time and, wow, it used a lot of def.  Now back to normal driving and it's still more than it was.  I'm guessing the update solved an emission issue with not running clean enough?

Im guessing so. The regeneration cycles are much more frequent now.

[Max Z71]

Mine REGENs about every 120 miles. I have a Banks iDash gauge and can see when it goes into REGEN.

 

What is your average distance between REGENs?

[ILSilverado]

20 minutes ago, Max Z71 said:

Mine REGENs about every 120 miles. I have a Banks iDash gauge and can see when it goes into REGEN.

 

What is your average distance between REGENs?

I have not measured mileage vs regens what is this gauge you have?

 

[Max Z71]

Check the internet for Banks iDash.

 

It is a 52 mm gauge made by Gale Banks that plugs into your OBD II port and reads hundreds of parameters from your truck.

 

One of those is called "REGEN". It tells me if Regen is "OFF" or "ACT" for active. It also has average miles between Regens which mine stays about 120 in my 2000 miles I've had my truck.

 

I have two of them, one for REGEN and the other for temperatures, oil, transmission and water as well as oil pressure.

 

Each gauge can display up to 8 different parameters. 

 

Max

[Sierra 3.0]

I do not have any specifics on my regens but it's doing it at least 2-3 times on each tank.  I'm a little disappointed in this as the fuel mileage goes down significantly each time.  If these did not have the emission controls the mileage would be incredible.  I have not seen my average to be anywhere near 29 MPG on the highway going 70 MPH.  My average mileage so far has only been around 24-25 MPG and the faster I go on the highway the lower it gets.  Then when regens hits I get 20 MPG.

Edited July 14, 2020 by Sierra 3.0

[newdude]

https://gm-techlink.com/?p=13143

 

Quote

Under certain conditions, the ECM will increase or decrease the amount of DEF used based on learning or adaptive algorithms. In the event of a malfunction and Check Engine light, the ECM may double or even eliminate the amount of DEF that is being used. An improper amount of DEF use will continue until the vehicle is repaired and the learned value in the ECM is reset.

 

 

I wouldn't doubt that the consumption rate will adjust as the ECM is learning/adapting.  Probably because the reprogram does a hard reset on the system, the ECM is still adjusting the amount of DEF needed.  I'd give it a few hundred miles and see what it does.  

Edited July 14, 2020 by newdude

[Grover67]

Suppose to have this update done Saturday, may have to reconsider if it makes it worse.

 

-Grover67

[Colossus]

Don't plan on being able to delete the emissions crap off of these newer trucks, the EPA has really cracked down hard on the tuners and such that help with emissions removal.