Why does the horn on my 2019 Holden Colorado beep twice roughly 30 seconds after locking?

Many cars will give a beep if they think the car has been locked with a door, bonnet, boot or window open, even slightly. But if you’re checked all that and everything is secure, the first thing to try is to reset the car’s body computer. The first way to try is to hold the lock button down on the remote for about 30 seconds. Sometimes this will force a reset.

If that doesn’t work, disconnect the car’s battery overnight and reconnect it next morning. You will have to rest your clock and radio station presets, but this will sometimes restore the computer to its factory settings. If none of that works, you may have a dud micro switch that’s giving the computer bad information, or the body computer itself may be on the way out.