You need a professional level scan tool to bleed ABS brakes ...hardly DIY
That's partially true. It really depends on what exactly someone is trying to accomplish. If it's just a brake fluid change, then this following routine will do just fine.
Remove the wheels and make sure that all of the bleeder screws are broken loose.
Put the rear brakes into maintenance mode. Turn the ignition off.
Use a suction device to remove the old fluid from the master cylinder reservoir.
Fill the master cylinder reservoir with fresh fluid. Dot 4 LV.
Install a brake holding tool.
Now one at a time, open a bleeder screw and push the caliper piston home. Tighten the screw and move onto the next caliper. BTW it does not matter which one you do first or last just do them all.
Remove the brake holding tool. Now at a moderate or slow pace, pump the pedal until it becomes firm having applied all of the brakes. Refill the reservoir.
Reinstall the brake holding tool and repeat the fluid removal from each caliper by opening the bleeder and pushing the piston back. Remove the brake holding tool and again pump the brakes until you have a firm pedal.
Refill the master cylinder and take the rear calipers out of maintenance mode.
Now yes, there will be "some" old fluid in the ABS controller but actually very little. As long as this is done before the fluid has significantly degraded the additives that enhance lubrication and prevent corrosion will be sufficiently recharged. As far as bleeding the rest of the ABS controller, all of the bleed valves would have remained closed so no air would be introduced to any area where it could be expelled to the rest of the system during an automatic braking or ABS event. If there would be a situation where a scan tool is required to complete bleeding the brake actuator there are a number of tools in the $500-$1000 range that are far from a professional level scan tool that would perform that routine.