On Wednesday my Yaris totally died on the M6 in the wet.

It's done it a few times in VERY WET motorway driving that it has stumbled and lost power (felt like fuel starvation but hard cuts, proper jerking) ECU light on and then it's fixed itself. Couldn't get to the bottom of it but suspected it was water getting in and interfering electrically somewhere.

This time it's totally dead. Same thing jerking and loss of power / inability to rev up properly but now it won't restart, even after drying out and I have 5 permanent and seemingly unrelated faults up at once where there were none at the start of the journey.

I've got:

P 1271 - Accelerator position

P 0089 - Suction control valve stuck (diesel pump)

P 0045 - Turbo boost sensor

P1228 - Injector short / intermittent fault

P0252 - Injection pump fuel metering control

These all seem pretty unrelated, have also seen ones for Mass air flow sensor and cam phase sensor come up after cranking etc.

Seems like a wiring fault somewhere? Any ideas for further investigation? I've had a good look at loom where I can access it. No big plugs seems intact everywhere and all the plugs are ampseal type ones, well sealed and clean and dry when I remove and reseat them..

Help!!