thats great harry_w,
but may i add a comment here relating to this issue.
i have found out also in the past that what makes these valves stick in the first place is dirty transmission fluid.
if the transmission isnt serviced regularly the fluid gets dirty and the dirt gets into the shuttle valve and makes it stick. When it gets to that stage you have to take everything apart and clean it to solve this problem. And i also have seen a few of these just go bad from bad coils as well.
Of course it giving an error code means an electrical issue so sounds like the coil was bad.

Laterz,