This what the service manual says, no mention of abs pump:
Rear Brake Caliper Bleed
1. Remove the rubber cap from the caliper bleed screw.
2. Attach a transparent tube to the bleed screw.
3. Place the other end of the tube in a suitable container containing new brake fluid.
The bleed screw should only be opened by a small angle, just enough to allow system
pressure to drop. When pulling the brake lever or pushing the caliper pistons in, some
resistance should be felt indicating that the screw is not opened too much.
4. Slowly apply and slowly release pressure to the brake pedal five times, maintaining pressure
on the final application.
5. Counter hold the brake hose union bolt and open the bleed screw slightly to allow fluid to flow
out but to still feel resistance in the brake pedal.
6. Close the bleed screw.
7. Slowly apply and slowly release pressure to the brake pedal five times, maintaining pressure
on the final application.
8. Counter hold the brake hose union bolt and open the bleed screw slightly to allow fluid to flow
out but to still feel resistance in the brake pedal.
9. Leave the bleed screw slightly open and slowly release the brake pedal.
10. Slowly apply and slowly release pressure to the brake lever five times.
11. Close the bleed screw.
12. Repeat steps 4 to 11 until no more air appears in the bleed tube/container.
13. With the brake lever still applied tighten the bleed screw to 6 Nm.
14. Fill the reservoir to the upper level with new DOT 4 fluid.
15. Remove the transparent bleed tube.
And if that doesnt work there is this, which is interesting:
Additional Bleeding (if required)
1. Remove the rear wheel (see Rear Wheel - Removal).
2. Remove the rear caliper fixings and move the caliper 10º anticlockwise on the brake disc.
3. Remove the cap from the rear bleed screw.
4. Attach a transparent tube to the bleed screw.
5. Place the other end of the tube in a suitable receptacle containing new brake fluid.
6. Slowly apply and slowly release pressure to the brake pedal five times, maintaining pressure
on the final application.
7. Partially open and close the caliper bleed screw slightly.
8. Repeat steps 6 to 7.
9. Slowly apply and slowly release pressure to the brake pedal five times, maintaining pressure
on the final application.
10. Open the bleed screw slightly to allow fluid to flow out but to still feel resistance in the brake
pedal.
11. Leave the bleed screw slightly open and slowly release the brake pedal.
12. Slowly apply and slowly release pressure to the brake pedal five times, closing the bleed
screw on the final application.
13. Repeat steps 7 to 13 until no more air appears in the bleed tube.
14. When all air has been expelled from the system, apply pressure to the brake pedal and close
the bleed screw and tighten it to 6 Nm.
15. Remove the bleed tube.