Suds error on whirlpool steam washer

My washer is showing a "Suds Error" and when I keep tyring to start it, the results is a "F35 Error". Trouble shooting guide points to bad pump.
Any further Ideas before I order this part?

— Begin quote from Ardvaark;479343

Replace pressure switch and use very little HE approved soap in the future. No more than an ounce.

Ardvaark

— End quote

Where can I find the part number?