Problems with remotely locking and unlocking a car's doors can be frustrating. Your Toyota Corolla is likely to experience remote locking issues from time to time just like all other vehicles of different makes and models. Whether your doors never unlock remotely or unlock only sometimes, you can do some quick troubleshooting to find out if the problem is with your Corolla or the remote keypad.
Most keypads operate on AG13 button-cell batteries. These batteries are typically used in power laser pointers and other small electronic devices. If your vehicle does not respond at all when you attempt to lock it remotely -- that is, the horn won't honk and the doors won't lock -- replace the battery in your keypad.
If you press the "lock" button on your keypad and none of the doors lock, but you are able to honk the horn, it is likely that internal wiring is the cause. This indicates that the Corolla is receiving the lock signal from the keypad but cannot execute it. Unless you are an experienced mechanic, you'll need to take the car to a dealership or repair shop to fix this problem.
If you are seeing an inconsistent response, where sometimes the door locks remotely and sometimes it won't, the keypad itself or the keypad receiver installed in your vehicle may be to blame. Installing replacement parts yourself can be done with minimal time and effort. Many auto repair shops and online outlets sell do-it-yourself kits for this situation.