Speedometer problems

[Fonz]

2016 Sea-Doo wake 155. I just had the actuator replaced by the dealer and first time out on the water my speedometer reading is way off. I contacted the dealer and they thought it might have been switched to miles per hour from kilometres per hour by accident. No big deal if that’s the issue. I went out on it with my phone app for speed and while it read 70 km an hour the machine was only showing 14 by the gauge. When doing 50 km an hour by my phone it was only registering 13 on the gauge. Is there a way to check the sending unit for the speedometer?