Double lock troubleshoot

[defever]

Hello dear Yaris 2nd generation owners,

I am very new to the forum and I would like to ask for your help on my wife's little Yaris (detail on my signature), please.

She's having some issues with double lock mechanism; the O/S rear passenger door sometimes becomes stuck on "lock" when double locked with remote key. The lock button by the door lever on the inside seems to be stuck on lock even all the other doors are unlocked via remote central locking. I managed to release it with forcing the button to stay "unlocked" while I pressed lock/unlock button on the remote key repeatedly until it eventually released the lock.

I tried to troubleshoot what is actually happening, and since I unlocked the door in question, every time I double lock the doors there is a horrible "GRRRRR" noise from the inside of the same door, as if something is grinding or a gear not engaging. This doesn't happen on single lock, only happens on double lock. It's just the O/S rear door that's faulty, other door locks are perfectly operational (for now).

I'm not familiar with Toyota (I'm familiar with VW/Audi Group), but I'm assuming there is a fault in some sort of door lock actuator or pump/motor. It would be very helpful if I can ask for advice or suggestion on how I can go about troubleshooting/diagnosing what might be a suspect, whether it is DIYable fault, and where people usually source Toyota parts.

Many thanks in advance and happy motoring!

 

[defever]

 

Has anyone experienced this or help me give right direction to troubleshoot?

Many thanks and happy motoring!