Many car manufacturers combine power door locks with alarm. The power door locks and trunk can be opened and closed with the alarm handheld transmitter key fob. The system is often called a remote entry system. Problems with remote entry systems on the alarm handheld transmitter can be related to the power supply, and to the coding. These kinds of issues can be corrected by following some troubleshooting steps.
Place the vehicle in "Park" or "Neutral." The remote entry system often won't work otherwise.
Try to open the car doors with the key fob. Press the button marked "Open" or similar. Sometimes it will be marked with an open padlock clasp icon. Try the driver's door. Press the button twice to try the other doors if the driver's door won't open. Press the button marked with a locked clasp icon and see if you can lock the doors instead.
Replace the battery on the remote control fob if you continue not to be able to open or close the doors. Often you need to slide open, or unclip a battery compartment cover, to change the battery. The batteries are often CR2020 or CR1616 -- the flat hearing-aid and wrist-watch type.
Place the alarm fob in your pocket for a minute or two on cold days if it won't open the doors. The range of the transmitter can be affected by cold temperatures.
Make sure you're using the correct remote transmitter key fob. Transmitters programmed for one car will not work on another. Additional transmitters can be purchased from a dealer if you've lost the one that works with your car.
