False Alarms with Onbord-TVSS-System

fittus

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I am in austria
Jun 18, 2016
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Hello,

is anybody out there, who can confirm problems with permanently false alarms of the TVSS-Alarm-System?

We have some LC100 cars in our pool and all of them have this problem!?
Year of construction of all cars is 2006.

In some cases i have found that sun shining triggers false alarms.

What is the right position of the rear ultrasonic sensor?

Our Toyota Dealer isn't able to solve this problem and therefore i only can solve this by myself. I need a curcuit diagram.

Thanks for your qualified reply and help.

FS
 

Towpack

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I had a similar problem on an earlier (1998) 80 series with the TVSS3B system in hot weather and cured it by tweaking the glass breakage sensor. It seemed to happen more when the car was cooling down. I surmised it was akin to the 'cooling tick' from a hot exhaust when the engine is stopped. No idea if the later 100 series has the 3B system or some later evolution of it or where the alarm ECU is situated though.
 
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Chris

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The full install guide was posted for the 80 on here recently. Very useful reading. I am guessing that the 100 series TVSS install is going to be very similar. It goes through installation, set up and fault analysis. There is a sequence you can go through to test all of its circuits.
 
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fittus

New Member
I am in austria
Jun 18, 2016
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Hello Frank,

yes after an alarm event the TVSS is always sharpened. There are situations, where the alarm siren is going every couple of minutes.

It could be the radar sensor, which is located in the center console. I should cutting off all the sensors, one after the other and watch, if the failure comes again. I hope, that the TVSS continues to work, if i separating one sensor?
 

fittus

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I am in austria
Jun 18, 2016
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Thanks to Towpack for the link. There a further links to pdf-documents, which are very helpful for analysis.
 

Chris

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Yes, mine worked with sensors unplugged. There didn't seem to be any detection of that circuit necessary. Mine turned out to be a faulty pcb in the sounder.

When yours go off can you silence them with the key fob? Mine wouldn't. Once it went off, I had to pull the sounder out of the wing and disconnect it. It's strange that you have several cars doing it. Points to a common fault doesn't it.
 

uHu

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Iirc, there's a procedure to disable the internal movement sensor, so that you can find out if that's the problem.

Otherwise, the most common problem with the alarm on the 100, is a plug in the bottom left corner of the liftgate. This plug, connecting the dome-light switch at the lift-gate-lock, is wrapped in foam. This anti rattle foam soaks up water, so that the plug/connector is always wet, and corroding. The fix is to remove the foam and clean the plug, or change it if it is bad.
 

Towpack

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With the TVSS on the 80 series, a second press of the arming button disables the internal movement sensor . Not sure if the 100 series is the same though.
 

frank rabbets

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I'd forgotten but my 100 alarm went off several times a few years ago. I could or reproduce the fault when getting home. I have not used the alarm since but yesterday read the owners handbook which is completely impossible to follow. Also looked on toyo diy but no clues as to type of alarm there. The early 100 has a different alarm to the later ones, at least my 2004 100 is different to Jon's. They seam to change alarm types every few years perhaps for better security.

uHu is this plug inside the top tailgate with the glass?
 
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