SCR System Fault- 2011 Mack

2011 Mack CXU613. First would ask for a parked regen. It was unable to complete the regen. Temperature would only reach 667°F. Now it shows a engine in derate and I've noticed DEF gage has dropped to 0. Ran a gage test and it seems to work. Just reads 0. Only active code showing is ambient temperature which I just replaced the sensor but code still active

 

Already have. Tried a forced regen and it won't even initiate.

 

There are no regen data numbers. Regen doesn't even initiate. Tried to force regen but It will not initiate. Only active code is ambient temperature

 

I do have a laptop. I can't monitor anything without the regen starting. I can't look at temperature. Pressure. Nothing since it won't even initiate the regen anymore. Truck stays in idle when I force the regen. Laptop and dash screen show regen in progress but the truck is in idle the whole time.only active fault code is ambient temperature and not inactive codes

 

I have a Snap-on prolink ultra scan tool with Volvo/Mack diagnostic software. With a repair connect subscription