Def fluid
#2
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
#5
Senior Member
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.
#6
0.9% is for suckers!
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
depending on how you roll, I usually see 4000 miles before I need more
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#10
Senior Member/Vietnam Vet
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.