diff --git a/Tools/autotest/ardusub.py b/Tools/autotest/ardusub.py
index 1339d78431..fcc622ddfb 100644
--- a/Tools/autotest/ardusub.py
+++ b/Tools/autotest/ardusub.py
@@ -422,7 +422,6 @@ class AutoTestSub(vehicle_test_suite.TestSuite):
         ret = super(AutoTestSub, self).disabled_tests()
         ret.update({
             "ConfigErrorLoop": "Sub does not instantiate AP_Stats.  Also see https://github.com/ArduPilot/ardupilot/issues/10247",  # noqa
-            "MAV_CMD_DO_CHANGE_SPEED": "Doesn't work",
         })
         return ret
 
@@ -458,21 +457,18 @@ class AutoTestSub(vehicle_test_suite.TestSuite):
     def MAV_CMD_DO_CHANGE_SPEED(self):
         '''ensure vehicle changes speeds when DO_CHANGE_SPEED received'''
         items = [
-            (mavutil.mavlink.MAV_CMD_NAV_WAYPOINT, 2000, 0, 0),
+            (mavutil.mavlink.MAV_CMD_NAV_WAYPOINT, 2000, 0, -1),
             (mavutil.mavlink.MAV_CMD_NAV_RETURN_TO_LAUNCH, 0, 0, 0),
         ]
-        items = []
-        for i in range(0, 2000, 10):
-            items.append((mavutil.mavlink.MAV_CMD_NAV_WAYPOINT, i, 0, 0))
         self.upload_simple_relhome_mission(items)
-
         self.wait_ready_to_arm()
         self.arm_vehicle()
         self.run_cmd(mavutil.mavlink.MAV_CMD_MISSION_START)
+        self.progress("SENT MISSION START")
         for run_cmd in self.run_cmd, self.run_cmd_int:
-            for speed in [1, 2, 3, 1]:
+            for speed in [1, 1.5, 0.5]:
                 run_cmd(mavutil.mavlink.MAV_CMD_DO_CHANGE_SPEED, p2=speed)
-                self.wait_groundspeed(speed-0.02, speed+0.02, minimum_duration=2)
+                self.wait_groundspeed(speed-0.2, speed+0.2, minimum_duration=2, timeout=60)
         self.disarm_vehicle()
 
     def _MAV_CMD_CONDITION_YAW(self, run_cmd):