My wife's 2011 Mazda 2 DE Genki (Australian market) has an issue with the door locks that is driving us insane. Here's a rundown of the symptoms:

• When locked with the remote, all four doors sometimes make a noise as though they are responding, but they don't actually lock. The locking mechanisms in each door move, but it's like they get to a certain point and then reverse.
• This can happen repeatedly. There have been times when I have tried to lock the car 10+ times and it keeps failing, but then suddenly, it locks fine.
• When the doors are failing to lock with the remote, I have also tried using the key instead. The locks even fail to lock when the driver's side door is locked with the key. When the driver's side door lock is turned (to lock the door), all the other doors attempt to lock also, but the locking fails in all four doors. Again, it's as if the doors tried to lock but bounced back.
• The door locking can sometimes be an issue for a few days, then suddenly, the issue is completely gone and the doors all lock without issue using the remote. Sometimes, everything behaves for a week or more, but then suddenly, the dock lock issue reappears.
• I've replaced the key fob battery but that didn't help.
• I've removed all aftermarket electrical items (Android head unit, heads-up display, LED interior bulbs), but that didn't help.

Any thoughts on what might be the issue would be greatly appreciated. Thanks!

 

[QUOTE=J0NS;234004]My wife's 2011 Mazda 2 DE Genki (Australian market) has an issue with the door locks that is driving us insane. Here's a rundown of the symptoms:

• When locked with the remote, all four doors sometimes make a noise as though they are responding, but they don't actually lock. The locking mechanisms in each door move, but it's like they get to a certain point and then reverse.
• This can happen repeatedly. There have been times when I have tried to lock the car 10+ times and it keeps failing, but then suddenly, it locks fine.
• When the doors are failing to lock with the remote, I have also tried using the key instead. The locks even fail to lock when the driver's side door is locked with the key. When the driver's side door lock is turned (to lock the door), all the other doors attempt to lock also, but the locking fails in all four doors. Again, it's as if the doors tried to lock but bounced back.
• The door locking can sometimes be an issue for a few days, then suddenly, the issue is completely gone and the doors all lock without issue using the remote. Sometimes, everything behaves for a week or more, but then suddenly, the dock lock issue reappears.
• I've replaced the key fob battery but that didn't help.
• I've removed all aftermarket electrical items (Android head unit, heads-up display, LED interior bulbs), but that didn't help.Any thoughts on what might be the issue would be greatly appreciated. Thanks.

The Body Control Module (BCM) manages the locks and might have a faulty relay.

Test: If you hear a "clicking" sound from under the dashboard but no locking action, the BCM relay could be weak.

Fix: A professional scan tool (or Mazda dealer) can check BCM error codes. Replacing the relay might fix it

 

[QUOTE=Riaan34;234006] This is the most common cause and easy for most DIY to try first!!
We keep dozen of relays and fuses in the shop. It is so common that I seldom write a work order and only charge them for the part.
Because the power protection box is under the hood it is constantly under several extreme temperature changes that can wear a rely on out. Most vehicles over 10 years will at some point have relays start to fail.

My thoughts it is an inexpensive and easy to do preventative DIY service to just replace all the fusses and relays in the under-hood fuse/relay on box if you are over 150k miles or over 10 years

Don't forget to do a battery load test at least every season change (free at many Autoparts stores) , disconnecting the terminals at the battery and cleaning them as well disconnecting the ground cable at its gorund sorce mounting area and cleaning and making sure clean bare metal, lastly check the cable to the starter for good clean contact.