Def fluid
 

Is it safe to assume that since I am using up the fluid that my truck is regening? Never see it in my screen

whenever the exhaust is hot enough to go into regeneration either active or passive you are using def. there will be a warning light that comes on when you get low. if you ignore it you will go into derate and eventually be limited to 5 mph

Ok yea I fill myself when hits about the 400 mile mark just never see the regen indicator come on. As long as it's working I guess no worries! Thanks

The DEF fluid is for driving, not regens.

AGREED! Read your power stroke supplement in the manual. DEF (diesel exhaust fluid) is used to combat emissions by spraying the urea into the exhaust system to breakdown NOx. A diesel particulate filter (DPF) is used to remove soot from the exhaust. Once the DPF is determined to be at capacity, a regeneration process is launched to burn-off the collected soot and carbon by running the exhaust gas temperature at the elevated level necessary to clear the filter.

on my 2009 and 2011 the light would stay on forever it seemed like, my 2012 its on/off in just sec.

depending on how you roll, I usually see 4000 miles before I need more

Been watching, nothing! Oh well let it blow it's under warranty

If you get an Edge Insight CTS, you will find yourself watching to see if the regen is ever going to stop. Mine usually go on for 20-30 miles.

If you are actually traveling and not be bopping around town, you will use next to none def fluid because your exhaust will be hot enough to literally break it down.

There is a misunderstanding of what the DEF is used for. It is sprayed into the exhaust SCR to reduce NOx, which goes up with the exhaust temperature, so the harder the engine works, the more NOx is produced and the more DEF is used. The regen process to remove soot from the DPF happens passively when EGT4 gets above 700 degrees, and actively when soot indicators indicate the DPF is full of soot by injecting extra fuel into the exhaust system. While there is only a 2 second indicator on the dash, the active regen process lasts for 12-30 miles in my truck, a 2015.