Why is my power tailgate constantly trying to open and close by itself

"Hi,

When it happens can you stop it if you engage the vehicle in gear when the vehicle is stationary?

Does it occur when driving?

If the answers to the above are Yes and No then it may be an intermittently faulty left or right side pinch sensor (part #13)

Update (12/31/2021)

@ckmoybriarfield1

The pinch sensor is still available if you search for the part # only i.e. 4894033AE for left and 4894032AE for right.

I was intrigued by your question so looked up the service manual where it stated that the liftgate would not operate under the conditions I stated above so I mentioned the pinch sensors as one possible cause that it might when the car was not moving.

That is not to say that it is the cause of the problem. The liftgate can operate due to inputs for other things such as keyless entry or driver side liftgate key operation.

I thought of the sensors because if one detected, incorrectly that there was an “obstruction” when closing it would stop and open the liftgate and when the “obstruction” was removed it would close it again. An intermittently faulty sensor could cause this more than say a faulty switch although they could as well, but you have to start somewhere.

Maybe try placing an obstruction e.g. box, in the liftgate area and check that it does do what it’s supposed to do when closing i.e. encounter the obstruction and auto reopens and then tries to close again properly when the obstruction is removed

Alternatively, you could try disconnecting one sensor (they are in series connection so effectively both are disconnected - see 2nd image, p.8W-61-19) and see if the problem stops. Hopefully doing this won’t cause any other problems ;-)

As seen in the attached images it is getting a bit involved with all the electronics as everything is controlled by the liftgate control module, in conjunction with the power train control module and the body control module.

There is a scan tool available (presumably at dealers) that can test the operation of all the modules and check for any error codes that may be stored.

(hover the cursor over the image and click on the magnifying glass symbol to enlarge, when the new window opens with the image, click on the image again to enlarge it even further)

I don’t know what will happen if you disconnect the power to the liftgate, except possibly that it cannot be opened. You may get indications of a liftgate open condition, even though it is shut due to no power through the modules etc"