So I got hold of the toyota repair manual for the car (1 day subscription online) and followed right through the diagnostic procedure for P0200, checking resistance of all the injectors (fine), wire harness (fine), EDU to ECM harness (fine) and voltage circuit from battery to EDU (12.54V - also fine).
Following the repair manual this leads you to the conclusion there is an open circuit in the EDU somewhere causing the problem.
Planning to order the EDU (DENSO driver injector - part # 89871-25010) and install it myself, but wondering what the hell the crackling/electrical noise is coming from the part I've taken photos of (it's not the EDU):
The noise can be heard with key on/ engine off, pretty sure it's not normal - any ideas?
Photos below - I've circled the part, I think it's something to do with the EGR. https://drive.google.com/open?id=1L9JlT ... E05OwjnE9ghttps://drive.google.com/open?id=1c6Ko_ ... Ea0j5UwHuD