U0155 is a network fault to the vnt controller on the turbo. It may be the turbo, but usually a vnt failure is a U0073 and a P0045.
Check all the harness connectors for bent pins and stuff. There is a sub harness for the vnt and it may simply be partially unplugged. Ive seen that before.
U0101 sometimes appears just from attaching a scan tool.
Clean every single ground, especially the one from left rear of cab to frame. Load test all batteries, replace any that fail. Clean and tighten all battery connections. Check alternator output, check for more than half a volt of ac voltage.
Has the intake throttle valve been modified? If not, do it. It also cannot have any shaft play.
Check the turbo for excessive radial and axial endplay. Spin it. Does it seem to seize when a slight amount of pressure is put on the side of the shaft while spinning it? If so, replace it. This is important.
Has the dealer done an scv test? If not, they are a bunch of jacklegs. Ask them to graph and print the results of an scv test. And email you a copy. Then send it to me.
Is there soot in the tailpipe? Get a dx report. It will have maximum dpr outlet temp on it somewhere, I want to know that number. And I also want to know what the exhaust brake setting is.
Thank you for reply
We've checked intake throttle and it does have three holes in it, that was some oily residue in there we had to clean up
Also, had rubber pipe between turbo and mass flow air sensor loosed and damaged (from swinging around). Replaced that.
Then have found some free end ground wire, that we have put back. checked other grounds and connectors (cleaned some)
else looked just fine
After all that Check Engine light showed up just once, and after a restart never again
It seems to have most(all) of the power back now
But, its still 40mph during auto regen
The dealer first refused to give us any reports. but then finally said they will email that to us. never did yet, we'll call them tomorrow
I did activation test on 980rpm (warmed up to 180F) - holds rpm in a range of 975-983
injection quantity stays around 9.9 mm3/st (9.45 - 10.55)
with the exhaust brake applied (temp goes up to 187F)
it gives an avarage of 19.9 mm3/st
Ran it on 1500 rpm (holds in a range of 1497-1503)
injection stays pretty much at 15 mm3/st fluctuates 14.80-16.10
In the sysem protection data it has
max exhaust temp for monitor 1 - 1,215F
max exhaust temp for monitor 2 - 1,085F
DPR seems to work good (hits 3 bars - auto regens to 0)
though has a little bit of soot in a tail pipe
I will send you SCV test report once they will send that to us (hope they will)
Thanks again,
Igor
