Anti-Theft Alarm And Flat Battery

br1anstorm · February 16, 2012

I have just posted a request for advice on dealing with a flat Battery in my IS300. I have also been looking through the forums and my drivers-manual for advice and clues, and this has raised another question.

I discovered the "flat battery" problem when I could not even open the doors. The wireless remote unlock wouldn't work.

So (almost without thinking!) I opened the drivers' door with the key. It opened. There was no alarm or anything. I put the key into the ignition and turned it on. Nothing. Then I looked at the interior light. Nothing. So I jumped to the conclusion that the Battery was flat, and went on to try to charge it.

I have since been re-reading the manual, and find that it says that - if the car is locked with the remote (which mine was) and then is opened physically with the key, the anti-theft alarm will go off. Mine didn't.

Obvious question - if the Battery was totally flat, would this in fact mean there is insufficient power even to set off the alarm? Or is there some sort of back-up power for the alarm? If so, why didn't mine go off when I opened the door with the key?

So I am now wondering - has something gone wrong with the alarm/immobiliser set-up - and if so have I inadvertently made the problem worse by trying to charge, and then disconnecting, the Battery?

br1anstorm · February 16, 2012

Just to update (and close?) my own thread. It seems there wasn't a problem with the alarm/immobiliser, and now that the Battery is recharged and reconnected, all is well. The only thing I had to be prepared for was that, as soon as I reconnected the (charged) Battery, the alarm went off - so I had to then switch it off using the wireless remote key .