I've searched the forums and found topics similar to mine, but not exactly the same situation. I apologize in advance if this has been discussed. Just point me in the right direction and I will leave amicably.

I just purchased a 2000 Honda Odyssey LX. The battery was dead at the dealer and when they tried to jump it the "alarm" would go off when they started the car. It goes off for 2 "cycles" then stops (you can hear a delay and then it starts again... it does this two times). They pulled the horn relay so I could test drive it and have it checked out. The lights still flash after I start the car and I can hear the clicking inside the car. I bought the car and replaced the battery but it's still doing it. Based on online research, I've searched for the valet switch but cannot find it. I don't know if this is an alarm or the panic button problem. I did not get a remote fob with the key. It only happens when it starts and does eventually stop after a minute or so. Obviously, I cannot get the van inspected until this is fixed because the horn is still disabled. I purchased an Owners Manual, but have not received it yet. Plus, I've read online that the manual doesn't really help with alarm issues.

Any ideas? Thank you in advance for your time.

 

If its a factory alarm, it should be disabled when you unlock the door with a key.

Its possible that your driver door lock actuator has gone bad. Next time try unlocking the car form the passenger side door. If you start the car and the alarm does not go off, it is in fact the driver door actuator that is faulty.