Sorry for the late reply!
STC forgive me messing with your mental health I have that problem with most people !
What I meant was I can talk to ABS module and parameters which are throwing C1130 and C1132 codes and what this is saying is the ABS unit is not able to talk to engine control module.
Scan tool connects to engine ECU ok also. (saying that hella gutmann ok Autoboss throws every code stored in ecm up)
I never got to the end of this and not had the time to spend anymore time on her at the moment.
I think the C codes are ghost codes and not coms error as if the p0471is cleared the slip lights go out but soon come back with p0471.
I think you are correct in what you are saying, Ive seen a Nissan bulletin regarding c1130 and c1132 coming on through the dpf blocked or blocked pipework, there is one pipe on the dpf going to pressure sensor this is all clear and in good health, a metal pipe going from the exhaust manifold and this can get clogged also but clean with no blockages! The car was reading 22 grams of soot which is to much , The dpf was not in good condition so has been changed codes cleared and live data still reading 22 grams of soot eh!, The pressure sensor has been tested on bench with mity vac and dvom and all looks good even when on the car the data at the pressure sensor is reading the same at ECM, continuity to ecm all ok.
Could it be EGR ? or faulty ECM software ?
As you say U codes are probably invalid data also as STC says the can looks ok, Just a quick question also how do find the topology of a network?