Have Toyota Questions? Ask a Mechanic for Answers ASAP
Hello, thanks for posting
This happens on some aftermarket alarm systems when the battery is disconnecteded, not knowing which system you may have try this first and let me know if it worked for you:
Remove the key from the ignition
disconnect the negative battery cable
insert the key and turn to ON ,leave door open
Reconnect the battery
Yes, the alarm re set and it will be ok until the next time the battery is disconnected but now you know how to fix it.
Please take a moment to rate my answer, thanks.