2003 / Is200 Alarm Problems

[leighw20]

Hi, I wonder if anyone can help, my 03, IS200's alarm has started going off randomly, sometimes its once every couple of days, other times its 2/3 times a day. I have checked basics, no water in fuse box, all contacts seem good, Battery appear to be ok, anyone know of anything else I can check ?

It is going into my local lexus dealer on Tuesday for a diagnostic check, based on the fact that they told me the ECU does register alarm faults, however I find it difficult to believe that the ECU will be able to highlight where the fault is. I just get the funny feeling that I am going to give them over £50 for a diagnostic check and it will show nothing,

Has anyone else exeperienced a similar problem nnd can offer any advice, suggestions.

THanks a lot,

Leigh

[fjcfarrar]

Hi, I wonder if anyone can help, my 03, IS200's alarm has started going off randomly, sometimes its once every couple of days, other times its 2/3 times a day. I have checked basics, no water in fuse box, all contacts seem good, battery appear to be ok, anyone know of anything else I can check ?

It is going into my local lexus dealer on Tuesday for a diagnostic check, based on the fact that they told me the ECU does register alarm faults, however I find it difficult to believe that the ECU will be able to highlight where the fault is. I just get the funny feeling that I am going to give them over £50 for a diagnostic check and it will show nothing,

Has anyone else exeperienced a similar problem nnd can offer any advice, suggestions.

THanks a lot,

Leigh

Check door-closure switches front and rear consistently operate the interior light. If intermittent can also cause auto head-lamps not to switch off. If you have to replace, be warned they are on very short, tight wires.

[janet]

I had this, solved it by having the interior sensor in the roof disconnected by the dealer....not saying it's your problem but it solved mine after embarrasing middle of the night problems (with the car that is!!!)

[leighw20]

Hi, I wonder if anyone can help, my 03, IS200's alarm has started going off randomly, sometimes its once every couple of days, other times its 2/3 times a day. I have checked basics, no water in fuse box, all contacts seem good, battery appear to be ok, anyone know of anything else I can check ?

It is going into my local lexus dealer on Tuesday for a diagnostic check, based on the fact that they told me the ECU does register alarm faults, however I find it difficult to believe that the ECU will be able to highlight where the fault is. I just get the funny feeling that I am going to give them over £50 for a diagnostic check and it will show nothing,

Has anyone else exeperienced a similar problem nnd can offer any advice, suggestions.

THanks a lot,

Leigh

Check door-closure switches front and rear consistently operate the interior light. If intermittent can also cause auto head-lamps not to switch off. If you have to replace, be warned they are on very short, tight wires.

Hi, I dont have any problems with the interior light, however the head lamps are usually switched off, not on auto, so I will try that by switching then to auto. Cheers.

[leighw20]

I had this, solved it by having the interior sensor in the roof disconnected by the dealer....not saying it's your problem but it solved mine after embarrasing middle of the night problems (with the car that is!!!)

Hiya, Thanks. Do you know if they picked up that the interior sensor was faulty by way of diagnosing it via the ECU ?

Cheers.

[MärkJ]

Check the obvious first. Make sure there are no flies/bees or anything else trapped inside the car. Happened to me before.

[janet]

I had this, solved it by having the interior sensor in the roof disconnected by the dealer....not saying it's your problem but it solved mine after embarrasing middle of the night problems (with the car that is!!!)

Hiya, Thanks. Do you know if they picked up that the interior sensor was faulty by way of diagnosing it via the ECU ?

Cheers.

It was more a case of trial and error, extensive trawling of the forum, ideas such as taking any metal out of the dash compartments etc etc, Lex suggested I went to there installers for a new alarm as cheapest option, but turned out the involvement of the ECU in the alarm made that impractical...so just asked dealer to drop the headlining and disconnect at my risk, didn't cost much but solved my problem.Rest of alarm works fine, no more keys by the bed 'just in case'!!

[Hoopedup]

Had the exact same problem with my 04 plate IS200, after much head scratching someone asked if i had any condensation on the inside windows which i did after all the snow we had, i think with all the snow getting dragged into the footwell it caused condensation which inturn activated the alarm during the night(motion sensor)I bought a moisture box from a caravan company and left it in the car for 6 weeks and had to empty it a right few times so deffo was moisture in the car.

Another thing i did was change the Battery in the fob, never had any bother since i done these two things.

[Yalnif]

Not sure about the IS but stock thatcham alarms do record said data. won't be exact like rear offside door but will say proximity/ motion sensor trigger, door/ boot/ bonnet switch sensor trigger.

You will need to check but alot of boots use mercury sensors to activate the 'boot open' light etc. these can go faulty. again, I'm not sure about the IS.

Hope that helps

Chris