Attention: TDR Forum Junkies 
Topzide
TDR MEMBER
On a trip home this weekend, got the dreaded ding! Looked down to see DEF gauge at ZERO. Of course this throws the truck into de-rate mode.
Was only 10 miles or less from where we started out from, so turned around to start looking for issue. Fortunately My FIL has a garage with lifts a short drive away.
Got it on lift and looking for any wire issues, saw white crystalline substance one DEF pump access plate! Removed the plate to find DEF dripping from the bottom of the pump! With AlfaOBD, I was able to confirm that the pump was working but leaking with more than a drip with pump running! All wiring connections were clean and free of corrosion. So that pointed to pump/gauge unit. Being a Sunday afternoon, no choice now but to limp back to where we we're staying and wait for places to open in morning!
Called first dealer to inquire about unit since they were 5 miles away with de-rate clock ticking. They didn't have but showed 2 others to call that were close. Called next closest and they had on the shelf.
Service said to bring in right away so they could get us back on the road. About 2 hrs and $2200 later, truck was done and we could get back on the road!
Morale of the post is to be on the look out for white crystals growing around the DEF tank access plate. If you see this happening, better take plate down and inspect to see what is going on! At least de-rate mode was following the odometer mileage and not "lie-o-meter" mileage!
Just another thing on the maintenance check list. Will keep an eye on DEF usage to see if it goes down.
Was only 10 miles or less from where we started out from, so turned around to start looking for issue. Fortunately My FIL has a garage with lifts a short drive away.Got it on lift and looking for any wire issues, saw white crystalline substance one DEF pump access plate! Removed the plate to find DEF dripping from the bottom of the pump! With AlfaOBD, I was able to confirm that the pump was working but leaking with more than a drip with pump running!
All wiring connections were clean and free of corrosion. So that pointed to pump/gauge unit. Being a Sunday afternoon, no choice now but to limp back to where we we're staying and wait for places to open in morning!Called first dealer to inquire about unit since they were 5 miles away with de-rate clock ticking. They didn't have but showed 2 others to call that were close. Called next closest and they had on the shelf.
Service said to bring in right away so they could get us back on the road. About 2 hrs and $2200 later, truck was done and we could get back on the road!
Morale of the post is to be on the look out for white crystals growing around the DEF tank access plate. If you see this happening, better take plate down and inspect to see what is going on! At least de-rate mode was following the odometer mileage and not "lie-o-meter" mileage!
Just another thing on the maintenance check list. Will keep an eye on DEF usage to see if it goes down. 
Now to talk the DW into a place with a shop, lift and acreage to enjoy the golden years! 
