98 GXL 3.4 V6 Immobiliser

[ebswift Lurker Find all posts View Profile Close ebswift]

Hi all, I've googled this to death yet I can't even find the immobiliser in my car, can anyone point out where to find the immobiliser ECU?

A little while back after my car sat for some time it would start but immediately stop. I assumed it might be an issue with the key, thinking it had gotten moisture in it so I put it in a container with some moisture absorbing satchels for half a day and the car worked. Thinking I had an unreliable key I got an after market one programmed and the car actually worked Ok for a few runs. Then it wouldn't start for me at work one day (using the new key), but finally did after an hour or so of head scratching but no changes to anything.

I'm guessing it could be the immobiliser - if I remove the chip from the (after market) key I get the same behaviour, with the car starting and immediately stopping. Oddly enough today when I try without the chip the car won't even start, it just cranks, so even that's not consistent. I can't reproduce the actual problem at the moment, the car starts every time, but there's obviously a problem developing.

Plan A is to pull the immobiliser and have a look at it, see if there's something obvious like a blown capacitor. Plan B is if there are any relays I can bypass, please give me the details on how to do so, even if it's in a PM. I can't use the car anymore for fear of getting stranded and I don't need an auto leccy yet until I check things out - especially while the problem can't even be easily reproduced.

Once I know where the immobiliser is, if need be I might be able to source one from the wreckers if they also have the master key - then I can get my new after market key reprogrammed to the new master. At least I hope... Otherwise, any pointers to anything aftermarket, or anyone who can do ECU repairs is welcome.

[RanJ Avid PP Poster! Find all posts View Profile Close RanJ]

the immobilizer is built into the ECU itself. Nothing to pull out and have a look at. What might be worth having a gander at is the transponder ring around the key barrel that reads the RFID chip in your key. Can also try changing it out as they do fail from time to time. These are not coded to the car so can be swapped at will. The key is coded to the ECU and the transponder ring is just a go between... albeit, a very important go between.

[croozza Avid PP Poster! Find all posts View Profile Close croozza]

I don't think that is quite right, as I had to have the immobiliser replaced about 6 years ago, it is a little black box that is under the dash on the drivers side. Only Toyota can replace it, as it is not a repairable part, at the time it cost just under a grand to do

[ebswift Lurker Find all posts View Profile Close ebswift]

I don't think that is quite right, as I had to have the immobiliser replaced about 6 years ago, it is a little black box that is under the dash on the drivers side. Only Toyota can replace it, as it is not a repairable part, at the time it cost just under a grand to do

I see two little black boxes under the ashtray, the one on the left says it's a relay module, the one on the right is a litttle more non-descript, is that the one? Yeah, I'm aware of the 1 grand replacement, though I did see another forum where someone had a repair done but never wrote back as to how/where.

Edit to say, if it's a grand and that's my only option then I'm happy to go that way rather than junk the car. I do like my Prado .

[ken2m Junior Member Find all posts View Profile Close ken2m]

I was just reading about someone who swapped the eprom (soldered in to circuit board) from their Prado into a replacement immobiliser and it worked fine. But having said that the immobiliser only reads the chip on starting. You can use a non chipped key to start provided you have the chipped key in contact with the other key. The car runs normaly until you switch off. key blank is TOY43. I use it when somone wants the radio on. Ken.

edit found the link a couple of posts down:
http://www.pradopoint.com/showthread...or-1998-5VZ-FE

lots of good stuff on pradopoint