Hello. It's called a door actuator, to be more specific. Is there any sounds coming from the door when you close it or open it? Any clicking, rattling, etc? Asking because, some door actuators are faulty because the control board - rear SAM Module - will become faulty because water will get in there. The reason water will get in there is because of the seal around the rear light will become brittle/compressed and will let water into the electrical area and all sorts of problems will occur.
First, check if there's water in there. If it's dry and no moisture then you can proceed to replace the door actuator.
If you change the door actuator first, and then get the same error the you'll be paying for work that you don't need.
The same mechanic that told you about the latch will be able to check the rear SAM module, with an obd reader. Google search on how to change the door actuator and watch a few videos, just to get an understanding. GL.