Service DEF, Regen Required... Just Kidding??

Sounds like best bet would to be clean the aftertreatment injector, DPF and DOC and diff pressure tubes for the regen issue. Also do you run a winter front? Engine temps might not be getting where they need to be.

As for the low Nox conversion Id start with checking the DEF doser for leakage and DEF crystalization buildup in the decomp tube. Could also just be an outlet Nox sensor issue.

 

Sounds like you definetally need to have the dpf cleaned or replaced... Probably some other stuff like listed by the post above.

I had exactly the same problem a few years back with the same make and year of truck with same engine... Dpf was nearly completely plugged.

 

Oh and just an FYI... Dpf problems are not the kind of problem you want a truck stop mechanic trying to fix... Take it to a dealer or other GOOD mechanic.

 

Usually when this happens it’s a wire harness check wires with fuse on top of the batteries or by the acm where Volvo put a splicer the where I would check first. How many miles?

 

I have a 2016 that does this randomly when it gets cold out. Shut the battery switch off, then undo the ECU and junction block connectors on the passenger side of the engine (3) by flipping the levers and pulling them out. Hit the pins and connectors with silicone spray then plug and unplug them a couple of times to wear off any corrosion. Turn the battery switch back on. Have your shop clear the codes.

Also check the main harness where it goes over the frame rail to see if it is rubbed through.

Another thing that will cause a ####load of codes is the wire harness for the crankcase pressure sensor rubbing through where it is attached to the metal bracket in front of the compressor.

 

Ur nox sensor is going to be the cheapest part in all of the problems this could be. Id start there and pull some codes.

 

You definitely need to get it scanned and see what fault codes are there.
Check for split clamps and leaking gaskets on the exhaust piping you might get lucky.

 

Most common causes of Nox conversion efficiency are: DEF contamination, Nox Sensors bad, DPF needs cleaned, or DPF Pressure sensor bad or tubes clogged. I would check those first.

Definitely still need software to look at codes first though. Thanks, DJ