I had the same problem with my Altis. I tried to fix it by opening the actuator for the door lock mechanism. I noticed it doen't have enough power to turn the mechanism. Fortunately, I looked around for a surplus part and luckily I was able to buy one (I think it's from a RAV4). Just bring the sample to make sure that it's exactly the same. Bought mine in Pampanga but saw a lot of it in Banawe. DIY project and cost me only P300.