Is this what pops up when you get bad def fluid?

Also dvrtech, the two codes that appeared on my computer were FMI 7 SPN 4349 and FMI 31 SPN 4794 when I had that alarm pop up. Im in a 2015 Kenworth t680 with paccar engine. Do you have a touch screen computer in your dash?

 

A friend recently bought a 2016 truck. First truck he has had requiring def . He buys his def at Walmart. He was told sometimes truckstop def can be contaminated. It's a Pete with a paccar engine. It has an apu , so hopefully didn't get idled too much. So far , so good.
My last truck was a 2003 Pete. No egr, dpf, or scr. If I ever buy another truck, I guess I'll get to learn about all kinds of systems I never had deal with before. Sounds great.

 

That sucks, must be the sensor like happened to me then.

 

I've had similar code on my DD16 several times.
Once it was exhaust manifold gasket leaking. It creates high NOx by interfering with the EGR amounts, then overwhelmes the emissions. But emissions system just sees it as insufficient DEF quality.
Another time was bad wiring to the DEF doser.
Another was solved with engine valve adjustment.
It can be caused by a multitude of issues.

 

I have two trucks in the shop who filled up at the same truck stop in Kentucky. Won't mention which one yet, may be legal actions. They both got down the road going to the same place and derated then screamed stop engine scream. The dealer can't figure out what is going on with them, they are throwing douser codes out, and they replaced everything but the DEF. so I told the service manager to pull the DEF sample and I'll pay for it to go get looked at - that is another $212 per truck. I'll have the results I hope Tuesday.

 

This is what you need.

OTR Reset Tool | Cummins