Lo all...

Got a very confusing but mostly frustrating problem with my IS250 Sport. After having it for a week the class III alarm (wich is built in by Lexus) starts living its own life. Firts time it went off while I drove on a roundabout, joined by a dash "Hood open" warning. Stopping the car, turning off the ignition and closing the car stopped the alarm. But that was after 5 minutes of an embarrasing drive.

My IS was silent for two weeks after that, when suddenly it decided to wake me up on a thursday at 4.30 in the bloody morning, for no reason whatsoever! Unlocking the car by remote and locking it again fixed it up.

Two weeks after this happening, I got both of them on my head. During a lovely drive the "Hood open" warning (accompanied by my lovely class III alarm) popped up again, forcing me to stop the car, close it and go off again. That same night my parked IS went off for no reason (again) this time at a lovely time of 6 in the morning! I allready got some strange looking neighbours before the alarm went bonkers, but nowadays they are starting to hate the car for its lovely concerts during the early hours! And I must say, it is'nt doing me any good either!

Lexus Eindhoven is aware of my problem but have'nt contacted me today about a lonecar I could use. I visited them past wednesday about this issue and they changed the settings of the sensors. So far the alarm did'nt go off while parked, but my "Hood open" symphony popped back up last friday.

NOTE: It appears my "Hood open" warning/alarm is triggered when I use the "close-doors" button from the inside. Might be related but then again I'm no rocketscientist...

Anybody have any of these problems or heared from someone who has?

Thanks in advance!

No, but it sounds like a dodgy "hood" sensor/alarm unit to me...but then...I thought the Immobilisor would immobilise the too...does the engine cut out when it happens while driving?

Nope, just keeps on going and going till the car is locked/ignition off. Been thinking of the faulty sensor as well but I can't understand why it would go off while driving (when the alarm is supposed to be off).

[quote name='Lexie' post='354587' date='May 22 2006, 01:38 PM']Nope, just keeps on going and going till the car is locked/ignition off. Been thinking of the faulty sensor as well but I can't understand why it would go off while driving (when the alarm is supposed to be off).[/quote]
One for our friendly "Lexus Specialists"...(aka the dealers)

short out your hood switch and try it for a few weeks

Sounds like the hood switch sensor has been tempted or not sit in properly and the alarm can go off anytime even left untouch. Any Auto Electrician can reposition or adjust it properly.

probably bad wiring for the hood switch, should not be an issue.

2 things to note:
- alarm will sound only for 30 secs, and you should be able to turn in off via unlocking the car, even during drive (depending on the car).

- Lexus alarms are not tied in with immobilizer. So your car wont shut off.


I would go to Lexus dealer for sorting out right away. They might need to replace the unit or not.

Agreed - I wouldn't muck around too much. I had a look under the bonnet this morning and could I see a switch anywhere? No. But then my eyesight ain't as good as it used to and I'm sure the switches must have changed since I last fitted any car alarms

One for the dealers - let us know what they find.

Got a bank holliday weekend coming up and am schedualled at the dealer for tuesday. I told them to keep it untill the problem is fixed since it's kinda embarassing.

As for the alarm going off for 30 seconds.... very true. And after those 30 secs, the warning remains and the symphony starts again.

Will keep you all posted and thanks for the feedback!

Got it back today! Seems there were powersurges (or losses) just behind the ignition (can't really find the correct english word). They did some limited rewiring/fuse adaption and were able to fix the problem. They didn't know if it was related to the "close-doors" button on the inside, could be. First 2nd gen IS they got back with issues, I just hope it stays that way.

Service was excellent, two thumbs up for Louwman Eindhoven!

Hope it helps...

Thanks.