The doors also lock on their own if you don't open the door within 30 seconds. They do this so if you accidentally press the unlock button while walking away, the car will lock itself.
If you unlock them and you DO open the driver door within 30 seconds, try unlocking them and opening the passenger front door. If the car doesn't lock within 30 seconds then the driver door handle switch is bad and not telling the car you opened the door. It thinks the door was never opened so it auto locks it.
Exactly ^^^. Another way to test this is through a VCDS cable. Go to Ross tech and buy a CAN enabled cable and software. It plugs into the OBD2 port and lets you see if the car's computer can see if the doors are opening or closing.
If you buy it and sell it as used then it'll probably cost less than the dealer. The test posted above is free and it can also confirm what the problem is.
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