Long story short, I plug a GEMs P8 ECU in, switch ignition on and there no fuel pump prime and the GWv4 also refuses to connect to it.

Plugging back in my other P8 (with Pectel Board) everything works flawlessly (fuel pump primes, ISCV tests etc), so it seems like an ECU fault.

Can I test anything easily top see if it is the GEMs ECU fault? I will also mail GEMs to see if they have any idea.

Thanks in advance!

Mark