yes there are about three cells which seem to be low and variable but they all come back to about the same voltage as the others - they cannot be lose since I never disconnected the individual cells but could the BMS boards be lose connected and need tightening?
Just measure the individual cells inside CMU09 block, if their voltage is identical then suspect the connections to the CMU board, if some of them are 100mV apart, bench balancing may be the way to go.
Now I know how the pack comes out this is not a massive task and have spare cells now to try to drop into this pack maybe.
I would strongly advise against putting some old cells into the new pack.
Would this issue be enough to make the OBC drop out from charging so maybe I am barking up the wrong tree and my original OBC is possibly ok and then might be all ok? Too may ifs in there!
Interesting point, clear the DTCs and start charging, if below CMU errors come back than it’s not a coincidence:
P1A7E cmu09 battery sensor abnormal
P1A33 CMU09 cell voltage sensor error
If they only appear during driving when putting the foot down, suspect the OBC.
Do I now try the non brick type charge lead which came with the donor car and see if that works in the hope that the OBC is actually matched to it? Do not suppose I can do much damage to the unit anyway and if it were to work - bingo?
Yes, no harm in trying but not much hope this will work.
I have a hunch that the 2015 OBC was modified to work with the 2010 car as it ignores the CP signal altogether, below is what your car expects
I would compare the two OBCs, in particular look for any differences from the plug E03 pin 9 leading to the innards of the OBC..