Turn OFF your-water for that sprinkler-zone
(if you have a manual-shut-off-valve for that-zone)
or before your-sprinkler-system
(like at the main-water-shut-off-valve).
Check the sprinkler-control-valve,
& control-wiring for that-zone;
Check your sprinkler-controller for that-zone
(compare OFF & ON valves/wiring & zones).
You need a continuity-tester or multi-meter
to check that sprinkle-control-valve/wiring, & sprinkler-controller.