I have a 2019 Mazda CX-9 and sometimes (like once a month or so) when I have the trunk door (liftgate) open, it starts closing automatically. I have been bruised a little bit by the door hitting me once or twice when I'm still organizing stuff in the trunk.

Is there a reason for this, or is it some malfunction ?

Sometimes I feel something triggers this automatic close, like a loud sound coming from nearby or putting down something heavy in the trunk. I could be completely wrong here though.

 

Does it have the optical switch where you wave your foot under the bumper and the liftgate actuates? If so, can you be inadvertently activating the switch?

 

If you're talking about the hands free liftgate operation, I think that's introduced in the 2020 CX-9, while I have the 2019 grand touring CX-9.

 

Any chance you had your keys in a pocket and the button got pushed when you leaned against something?

 

Yes that could be a possibility. I will try to make sure this doesn't happen.

Is it recommendable to show the car to a mazda service center since the car is less than a year old ?

 

Is there a way you can make it happen every time you make a certain action? Otherwise they'll report, "Problem not found." Then they'll probably charge you a diagnostic fee for finding and doing nothing. (The only part of a dealership that is more profitable than the service department is the so-called finance manager who tries to sell us all the overpriced stuff we don't need.)