What is the difference between these Power Steering Pump

[heliosGT]

Hi friends, 1 year ago the PS pump of my 2012 mazda 3 skyactiv Grand Touring broke, then i replace with a new one from dealer. But the EPS light on dash goes on and does not turn off but the handling is ok.

What is the difference between BFD132600 , BFD132600A, BFD132600B and BFD132600C power steering pump?

Thanks for help!