Alphard hybrid wont start - inverter - P3125?

[DW2023]

Hello All

My car wont start.

Its been a while and ive had plenty of people look at this car and it seems to be an Inverter issue.

It's a Japanese import

ATH10 - 0018786

4WD

Hybrid 2.4 2006 

7 seater

2AZ-FXE engine

It wont start, it just makes a humming/whizzing noise from under the bonnet when I turn the key and then cuts out. It doesn't sound healthy. Its never donr this before.

The error codes on techstream are

P3125 Inverter Malfunction

Sub Codes - 495,496,497 and the trickiest one seems to be 484

The inverter seems to be the main issue and have been told that the DC/DC converter is likely to be the issue and the sensors and it will have to be taken apart to find out. Trial and error. Makes sense to me. Ive been told by a couple of people that its possible to replace the faulty components for between £900 and £1500....... Or replace the whole inverter with a new £5.3K inverter.

But could also be the "wiring harness sensors" or the "motor generator"

Also has code

P0135 Oxygen Sensor Heater circuit (bank 1 Sensor 1)

But that can be fixed.

Inverters for this model are expensive and rare and i'll need to find a working one to test and see if thats the problem before buying a replacement. Have also been told that its possible to fix it without having to replace the whole thing but these sub error codes 495,496,497 and 484 are quite confusing.

Any ideas of who can help me? Any thoughts on these Sub error codes? Any solutions?

I live in London but I'm happy to take it on the back of a pick up truck to anywhere in the UK if anyone knows of a specialist who is confident that they can fix it.

I have called and spoken to lots and lots of mechanics already.

Thanks

David