100 VX electrical problem

Gary Stockton

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Hi all,

Jos from LCCSA has asked me to post this:

I hope you can help: I have Barries' L/C in my workshop and it is draining the main batteries within a few days. There is a 270mA drain which is causing this and I am convinced it is the backup battery of the TVSS (Toyota Vehicle Security System) which has died. The only problem is I don't know where it is located. Looking on the web site seems to confirm this diagnosis, but I cannot find any post where anyone has identified the battery's location.

Would you be so kind as to put up a post requesting this info?

Vehicle is 1999 LandCruiser 100VX 50th Anniversary Edition Turbo Diesel UK Spec (was imported into SA by previous owner)

There is a similar post elsewhere about this:
My 4.7 VX Amazon is draining the battery in a couple of days if I don't use it. I just had to fit a new 720A battery because 2 of the cells in my prevfious one had died. I measured the current drain with everything off and something was pulling 270mA. I went through the fuses one by one, pulling them until the drain reduced. There is a fuse in the Left hand side front of the car (I have a right hand drive) marked as ECU-B. Once I pulled this the current drain dropped to 70mA.

Does anybody know what ECU-B is?
Is this an easy part to replace?
Does anyone know approximate costs (in UK pounds would be helpful) or do I leave it and live with replacing a battery every 12 months as a cheaper alternative?

Cause remained unknown I think?
 

Jon Wildsmith

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I don't know where the back up battery is. The TVSS box is under the cente console, forwards of the gear selector, a little black box that says TVSS on it and has a sensitivity dial. Not sure that box does anything more than being a pressure wave sensor though. Has he checked the drain is through the ECU B fuse as per the second part of the post? The twin battery trucks can have a high current drain between the two batteries when one of them starts going bad.
 

Saskia

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Gary in this manual, www.mudtoys.com/manuals/100/05rm.pdf , there is an entire section on the theft deterrent system and it shows the Theft Deterrent ECU sits behind the glovebox, see page DI-634. The Theft deterrent ECU power source schematic is on page DI-640, but I only see the main battery, no back up battery. If you run a search on "ECU-B" it pops up quite a number of times and on various circuits.
 

Jos Hartog

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Thanks for all the help. It turns out the 270mA drain is normal with the vehicle unlocked. Once locked the drain drops to about 100mA which is acceptable.

PS, I found the backup battery for the TVSS but I'm not sure I should post the detail in the open. Anyone who needs this info is welcome to contact me.

Thanks again :clap:
 
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