Abs/TCS fault

Here goes for my first technical question.
i bought my pan with an abs fault. I checked the codes and it came up with fault 1. Front modulator sensor.
my questions are where is the modulator pump?
can the sensor be changed or do I have to change the unit?
my bike appears to run rough as if its dropping a cylinder. Is this to do with the ABS? Or, do I have a separate fault with the traction?
thanks in advance
john

John, ABS I (92 thru 95) or II (96 and later)?

John, ABS I (92 thru 95) or II (96 and later)?

Send a PM to Norm Keller (Norm on this site) in Canada. He's the ABS guru.

There's an article on how to bebuild modulators for the ABSI in the Archives Of Wisdom at st-riders.net. Norm is also a member over there. Couldn't find details on the ABSII. Honda sez those parts are not rebuildable but Norm researched the parts and figured out how to do it.

It's a 1993. So I'll assume it's ABS1