More tests done. Now it's been bled the best we can. Two iABS units with about 50000 miles use difference with now identical faults. No rear motor and internal pressures almost equal to each other. Unit put back on it's own bike, codes cleared and it works perfect. What could possibly be wrong with my bike please?
Have you checked things like the rear brake switch and the contacts on the brake light (globe)?
Does the brake light work properly? Some of the older bikes (1100/1150) used the tail lamp in the event of the brake lamp failing. That is why I ask the question. Do not just check that the brake globe lights up. Physically remove the globe and check the contacts on the globe as well as in the fitting.
On certain of the older models, depressing the rear brake pedal whilst turning on the ignition, disabled the ABS. So if the rear brake switch is not adjusted correctly, the system will think the brake is being depressed during the ignition on cycle.
The switch needs to be adjusted in such a way that the brake light comes on almost simultaneously to the pressure being applied to the system, if not fractionally before. If pressure is applied to the ABS system and the brake light has not yet come on, it will generate errors.
Lastly, does the rear master cylinder work and return smoothly? The same master cylinder is used on the early 650 ('00 - '07) and these often corrode inside, causing them to bind. In the event of this happening, the brake light will go out (since it is operated purely by the foot pedal position) but since the master cylinder is slow in returning, the pressure is still maintained in the ABS unit, and thus registers an error.
