I have a 2014 Mazda 3 - recently I have been having issues with the key fob where it will not consistently work to open the door or start the car. Sometimes I can press the unlock button, but I cant press the button on the car door. The same thing happened to the spare key.

I changed the battery and everything starting working again for about a week. Now I am having the same problem where about 50% of the time I can't open or start the car (I have to do it manually). Or I can open the door with the key button (not the door button) but still cant use the push start (I have to hold the key on the push button).

Any thoughts on what is happening?

 

Try cleaning it. I believe there is a YouTube video about cleaning Mazda fobs.

 

I'm having the same issue. I lost my extra key fob. I have a Mazda 3,2017.

 

I have a 2015 Mazda 3 hatchback and this happened to both of my key fobs. Replacing the batteries didn't fix the problem. I discovered the contacts touching the upper (+) ring were pushing the battery back enough to break contact with the bottom (-) side. I bent the upper contacts inward to reduce the force on the battery and carefully positioned the round battery cover. I even put a piece of folded up masking tape to press on the battery cover before I snapped the fob back together. This worked for me but if I'm going anyplace important I bring both fobs for insurance.