Thanks. He's in Austin, and unfortunately not here where I could give it a once over and probably figure it out. The local dealer has been scratching their head on this and replaced a bunch of parts and eventually decided that the whole unit needed to be replaced.
On my advice he took it to an independent, but according to him there aren't any Subaru specialists in Austin (which seems weird) and the shop he took it to (recommended by some Suby owners) told him they could swap it out with a used one but he'd need to take it ot the dealer for cycling the ABS. Well they swapped it in there and then told him he'd have to take it to dealer for coding. Got it to the dealer and they told him it's coded to the exact car and can only be replaced with a new virgin unit. So now he's looking at $1800 to replace (parts and labor), or being on the hook some god awful high dealer diagnostic fee.
If a used one would work it'll still be cheaper, and he's capable of doing the swap himself, but he's getting near the point where he says eff it and just pays the extortive dealer price. Does anyone have a P/N for the electrical bits? The only part number I could find was for the VDC hydraulic unit (27596AJ01A) with MSRP of $620, I couldn't tell from the parts catalog if that included the electronics. If I wasn't in school I'd just buy a cracked SSM and fly down there and swap the damn thing for him.