2016 Volvo d13 asking regen after regen.

Code I got:
Txld: 0 SPN: 4364 - Aftertreatment 1 SCR
Conversion Efficiency FMI: 31 (null) Count: 1

2 days ago got dashboard signal for parked regen. Did the regen (1 hr). Soot level dropped and I went my merry way.
Yesterday it asked for it again. Did the parked regen (spent 1 hr) but this time soot didn’t drop. So I did the second regen right after (back-to-back another 1 hr). Same picture. Soot level high.
Did the third one this morning. Didn’t help.
Took the 7th injector out and it looks pretty new, no build up. Took the def doser out. It shoots out from all 3 holes.

What should I check more, please help i’m in the middle of nowhere.

 

Do you have any other symptoms? Loss of power, whistling noise from the turbo, is the truck losing coolant?

 

Did not lose power. Coolant level is stable for 2 days that I was on the road.

 

It could be Nox Sensors. But I'd first check if there is a hole somewhere in the Exhaust System - check if there is any visible burn-like color on the Flex Pipe.
What is the mileage? When was the last time DEF Filter was cleaned?

 

If ther are no mechanical issues take a good look at your def filter, it could be no bueno no more. Sometimes is a simple thing like you and others mention, 7th injector, nox sensors even a bad def pump but most of the times is a dirty filter that a regen can't clean or a completely bad one.

 

NOx sensor was changed literally right before this trip (or so my mechanic says). How should I troubleshoot nox sensor?
No visible/leaking exhaust.

 

Milage is 560K. I bought it at 525K. Don’t know when was the filter changed.
I’ll be changing it and the doser.

 

It could be a clogged filter in the ash canister.
It could be a bad pair of sensors for exhaust pressure at that filter.
I would start with the sensors then move to remove the filter for an inspection.
Once removed you need new clamps.
You can't use the old ones.
If the filter needs cleaned up, you can burn it at a dealer or another shop.
Sometimes, owners just clean it themselves.
There are YouTube videos about this.
It may be the case for a new filter.
Aftermarket are fine and half the price of an OEM filter.

 

As soon as I get home probably will check dpf status again.

I went to mechanic before this trip to for if dpf filters need replacement. He said they are fine (I don’t know how he checked, probably just hooked up to computer). He said he “… changed NOx sensor and regened the truck which dropped the soot level to 25% or less”.
But… truck is asking parked regens more frequently (everyday). I drive only highway and keep the rpm at 1300-1500 and don’t idle often.
Do you know how those pressure sensors are called? A friend of mine coming my direction so he grabs parts.
Thank You!

 

How to check the DPF sensors on a 2016 Volvo VNL? - Bing video