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With the multitude of sensors and the issues I've experienced I like to record some data which will might help to troubleshoot future issues and give a some information which will indicate trouble coming up (plugged DPF).
Some info here:
https://en.wikipedia.org/wiki/On-board_diagnostics
https://en.wikipedia.org/wiki/OBD-II_PIDs

You need an OBD port interface. I got one of these:

And an app. I use TouchScan. I tried quite a few and this is the only one which will record data and read some of the not so common data items such as the EGT's and the DPF pressure drop. The developer was responsive to my questions and fixed a bug quickly. Torque seems to be the most popular app, but won't read the PIDS we need and the developer hasn't responded to emails or forum post (on his forum). OBD Auto Doctor is a nice one which reads the PIDS, but doesn't record the data.

Unfortunately some of the data we need is not in the default set so you have to set up some custom PIDS.
The PIDS that I've added are
EGT3, PID=78, equation = F*25.6+G/10-40, units C
EGT4, PID=78, equation = H*25.6+I/10-40
DPF pressure drop, PID=7A, equation=int16(256*B + C)*0.01, units kPa
[EGT1 is already in the default data as 'Catalyst Temperature'].

Here's how to do that in TouchScan.
Go to Settings->User-Defined PIDS, click menu then New, then fill in the fields.

So far I haven't seen anything very interesting. One thing I'm looking for is the DPF regeneration. When the DPF starts to get plugged up the DPF DP (delta pressure, pressure drop) will increase, the ECU commands a regeneration where extra fuel is injected late which heats up in the DOC which is supposed to burn off the soot in the DPF. My failed van wasn't doing this. So far, with a couple of hundred miles logging data I haven't seen a regeneration. It should show up with EGT's increasing. They go up and down quite a bit with load, but I don't see anything that stands out as a regen. The DPF dP hasn't changed much either.
 

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2014 Ram Promaster 2500 159" diesel
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Thanks for the custom pids and links. By the way obdlink and touchscan are the same obdlink is for Scantool only and touchscan is for elm327 I just compared them and saw no difference in the two android apps . They are both made by octech.
 
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