diff --git a/Tools/autotest/arducopter.py b/Tools/autotest/arducopter.py
index 8703b161d142d..1cb332597dfa9 100644
--- a/Tools/autotest/arducopter.py
+++ b/Tools/autotest/arducopter.py
@@ -9851,7 +9851,7 @@ def Sprayer(self):
 
         self.start_subtest("Checking mavlink commands")
         self.progress("Starting Sprayer")
-        self.run_cmd(mavutil.mavlink.MAV_CMD_DO_SPRAYER, p1=1)
+        self.run_cmd_int(mavutil.mavlink.MAV_CMD_DO_SPRAYER, p1=1)
 
         self.progress("Testing speed-ramping")
         self.wait_servo_channel_value(