i'd say you need an ABS pump. They are easily had, as many members take them off via ABS delete kit or have cars breaking
personally i've changed ABS pumps twice on my ep91, the first time i had an abs code 51 ( if i remember correctly, that was a long time ago) which indicated a faulty ABS pump, so i bought a used one cheaply from tgtt, but had to waith for it to ship to the Caribbean (1 to 2 weeks)
in the meantime, i found an ep91 n/a ABS pump, which looked basically the same and fit up perfectly, so i installed it and it worked great.....bleeding was no issue, just takes a little while to get flow through the abs, once you get flow from all ports on the abs, then you can hooking it the pipes and proceed to the normal bleeding procedure, so you know that the abs pump is working. The second time was to remove the perfectly working n/a ep91 abs pump to install the turbo ep91 abs pump that had finally arrived to my shores, again, it was relatively straight forward process, just takes a few pumps to get the air from the abs unit, but not an excessively long process that you have to be pumping for ages.
if i remember correctly, one of the ports on my original/broken abs pump was stuck/dry with no brake fluid was passing through