The valve to zone 2 more then likely has contamination inside (internally) and has now fauled up the valve.
Locate
the valve in question and take it apart- inspect the diaphram for
damage and flush the valve. Recommend to replace the diaphram.
Where abouts do you live?
DeSoto, Tx, a suburb of Dallas. I will get a sprinkler company to do the repair. In years past I would do it myself but now I have only one usable arm making digging quite a challenge. Btw, where is the zone 2 valve located.
Thanks