BM E36 325i Fault code '26' ECU voltage low. ?

Question

Had diagnostics run on my car (which is a non-starter) and got a 'ECU voltage low', bloke recons it's either the battery or starter motor. Had over 12v on the battery (which was new in May) and when we tried starting the car the battery dropped to 6v. (taken with a snap on machine)

Could an ECU voltage fault be caused by anything other than the battery/starter motor? Could it be a relay? I've tried googling the fault but can't get anything back, any help is appreciated.

Answer 1

test the starter. sounds like it is shorted out.