Hi phil,

There is no obvious reason for these valves to be failing just poor quality from my experience.

Cant get codes from workshop manual,as they are in the t4 diagnostic tool,(poor design)vehicle has to be plugged in to read fault description.

May be worth using a scope to view the can signals just to see whats going on.

p1647 in my book is `can data bus-defective,trouble codes stored in other systems`.

Is this vehicle fitted with a fuel burning heater by the battery?had trouble with one of those causing a can fault in the past.

cheers

lee