Just disconnect the battery when you fit them.

 

I was interested in some of these. Both terminals or just the neg?

 

The more the merrier :grin:

Seriously though, just the negative. I'm not sure why these possibly blow the BIU though.

 

Got some from Aliexpress more than a year ago. 5 minute job to install. In the mean time the logo is gone though, but oh well they were very cheap indeed

 

I installed some of these a while back. Didn't worry about the BCM because I used plastic trim tools. The issue normally crops up when someone uses a screwdriver and ends up shorting the wiring out. I spoke to a Toyota master tech before installing mine and mentioned this asking if it would be OK, and he looked at me as if I'd asked if bears poop in the woods.

As said, if you're really worried then just take off the battery's negative terminal.

 

The problem is if i disconnect the battery i will lose the immobiliser code. My car was fitted with a Sigma device when new and there is a numeric keypad in the glove box for which i don't have the code. I contacted the Toyota dealer from where i bought the car but they could not help.

I guess i will speak to my local car security experts to see if they can reset it for me as if and when the battery dies i am snookered.

 

That's the standard fit unit for the UK models, they all have the keypad. No issue disconnecting the battery as the immobiliser is done via the key.

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