leighv

Hi all,

I have a 2005 SC430 and all of a sudden the alarm is going off. Twice today once at 6am and then at 7.30am. Since then (it's nearly 2.30pm) - nothing.

I've not changed anything inside the car since it went off this morning - and nobody was trying to get into the car. The problem of course is that it autolocks and turns on the alarm.

This has only just recently started happening.

Any ideas?

Is there anyway just to lock the car and disable the alarm?

Many thanks.

mrblister

I READ THIS IN THE GX470 FORUM [ COULD BE SIMILAR ISSUE WITH A DOOR SWITCH OR PERHAPS THE TRUNK SWITCH OR HOOD SWITCH CAUSING THIS BELOW IS THE GX470 INFORMATION IN THAT THREAD



"I can't answer why it would possibly go off when the truck is unlocked but I can take a guess as to why it might be going off when locked.

It's a common problem with the GX470 that the rear door switch will eventually, not depress far enough to signal the vehicle that the rear door is closed. If you live somewhere where the temperatures are starting to cool off in the early hours, this may be your trouble.

Someone else may be able to indicate if you can adjust the switch or switch bumper or not but I don't think you can. I had the exact same problem and didn't want to purchase a new switch or switch bumper so I went to the local hardware store and purchased a black "Bump Stop" that was the same size as the existing bumper on the truck door. I just stuck the little bumper to the existing bumper so it would depress the switch another 1/8".

sixonemale

I'm in agreement with what mrblister found in the GX470 forum. I had this exact same issue with another vehicle that I owned and it was the door switch. Unless you can isolate this intermittent problem yourself, I'm fairly confident Lexus has a diagnostic tool that will be able to pinpoint exactly which switch has triggered the alarm to go off.

In my case the dealerships diagnostic scan tool was able to obtain recorded information from a computer chip within the car that identified the exact switch that was malfunctioning. Many times its the drivers door switch since it used most often.

Also, a couple of other clues that point to a door ajar switch/sensor is that the dome light will come on randomly when driving and/or sometimes the locks will randomly open and close due to the false sense that the door has opened and then closed.

HumphreySC

Had the same problem last month and put in a new alarm.

Yes you can close the car withou arming the alarm. The exact way how to do it is described in you owners manual.

After 8 years they do not have parts available for your alarm system, so if you keep the problems you have to invest in a new system.

It is really frustrating and in my situatiin tha alarm always went of at nights

mrblister

What part did your alarm system need ?? I would imagine that some parts for the sc430 were used in other cross platform lexus vehicles. . I think you might be getting a run around

I have a 2005 and I cant find in the owners manual how not to set the alarm and still lock the car. If you lock the doors and the key is not in the ignition the alarm auto goes on

HumphreySC

I do not know which part was broken, so I decided to put in a whole new alarm. I was fed up with it.

I have an owner manual in dutch, at page 132 it is described howyou have to close your car with your key without arming the alarm. I assume the content of the US manual is the same.

You have to close the door at the drivers side with your key and close the door at the passengers side manually by pushing the button in the door and close the door. I believe you have to hold the grip to get it done.

Good luck.

mrblister

When I lock my drivers side door with key both doors lock . When you take key out of ignition the security light flashes and once the door or doors are locked the alarm sets it self about a min late.

Your car must be different then the US cars .

Buddy

HumphreySC

I do not recognize this. Have you tried to close the door at the drivers side by hand by pushing the button and not use the key?

If this works try the same with the other door.

When I do this, only the drivers side closes....

mrblister

I will try this when I next use the car