Man I’m tired of these rotten DEF systems

[J&JD]

Beautiful 4 day stop at a really nice new rv park in Northern California. All packed up, everything secured for the trip home. Fire up the Cummins and damn if it doesn’t throw a check engine light and a message saying “low DEF”. My dash gauge shows 2 bars in the tank and I know there’s at least 1/2 tank as I had just visually checked it. Drove about 40 miles and stopped at a truck stop and filled the 13 gallon DEF with 7.5 gallons of truck stop DEF. Obviously I wasn’t low on DEF.
Drove about 20 miles with the check light on and all of a sudden the light goes out and the DEF gauge is back up to full (4 bars).
I’m on my second DEF sensor and now I’m worried that this one is going bad after just 20k miles. This is just stupid, poor engineering that should never happen with a system as expensive as this one.

 

[Joe Hogan]

In my opinion this DEF System is a wacky lab fix that escaped before or even ever ready for commercial applications.
Government dictates driving bad systems.
Early catalytic converters suffered similar problems that were finally fixed with widespread adoption of electronic fuel injection.

 

[Rich W.]

I think you would benefit from carrying a DSS with you because eventually this could lead to derate and all the fun that comes with it. You’ve probably seen this many times before but here it is again anyway: DEF Sensor Simulator

 

[Rich W.]

In my opinion this DEF System is a wacky lab fix that escaped before or even ever ready for commercial applications.
Government dictates driving bad systems.
Early catalytic converters suffered similar problems that were finally fixed with widespread adoption of electronic fuel injection.

Yeah Joe you’re right - this was forced on the public long before the engineering was sufficient to develop reliable systems. And to illustrate that point, they had to exempt emergency vehicles and because it was considered an “undue hardship”, agricultural equipment as well. I’ve always said that it is also an undue hardship to have your home on wheels leave you stranded by this equipment but apparently we don’t have a loud enough voice. Fortunately around 12 years after the mandate they finally appear to have developed a reliable system; time will tell.

 

[J&JD]

I think you would benefit from carrying a DSS with you because eventually this could lead to derate and all the fun that comes with it. You’ve probably seen this many times before but here it is again anyway: DEF Sensor Simulator

I do carry a simulator. I was/am hoping that I will not have to utilize it. Still doesn’t give me much piece of mind concerning this sad system.

I also carry a new DEF head. Has anyone tried to replace the head themselves? Can it be done without removing the tank on a DS 4018?

 

[Jim]

I do carry a simulator. I was/am hoping that I will not have to utilize it. Still doesn’t give me much piece of mind concerning this sad system.

I also carry a new DEF head. Has anyone tried to replace the head themselves? Can it be done without removing the tank on a DS 4018?

I considered it on my London Aire, and then quickly reconsidered it. Not a job I would want to take on.