Car was purchased new by me so I have all the history.
When the problem started back December last year, I connected up Citroen/Peugeot Diagbox tool (offline version) and read all the ECUs. Only DTCs were P1A15 and U1113. The car has always had U1113, there is a note in Diagbox to ignore this code.
I suspect something on the EVECU or upstream of the EVECU: the reason being the I can't hear any clacks from the contactors (after clearing DTCs)
My approach will be to confirm that the contactors actual energise (proving traction battery pack precharge resistor, HV wiring to MCU-Inverter, HV battery pack main fuse. Then I will record the C105, C106, C107 ECU outputs on a start and see which if any are energised.
If the negative contactor and precharge contactor do NOT energise, the problem is definitely in the EVECU or upstream. If they do, but the positive contactor does not energise, its time to isolate the heater, aircon and OBC in case of HV fault leakage. If the car still does not go into ready (still does not energise the positive main contactor), its time to start measuring the "condensor" voltage rise and compare a directly measured value with the value the EVECU is reporting.
Thats the general approach, any advice much appreciated