Immobiliser Stuck On

[ronaldo60]

I blew the main 120a fuse on a gs300 by jump starting backwards. Replaced the fuse and several others which blew. The immobiliser is now not reponding to the key, nor is the boot lid. The engine turns but will not start.

Any ideas short of calling the dealer?

Thanks for any help you can give.

Ronaldo.

[ajones1722]

I blew the main 120a fuse on a gs300 by jump starting backwards.  Replaced the fuse and several others which blew.  The immobiliser is now not reponding to the key, nor is the boot lid.  The engine turns but will not start.

Any ideas short of calling the dealer?

Thanks for any help you can give.

Ronaldo.

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when i recently disconnected the Battery to reset the ECU's the Lexus garage said after you reconnect the Battery put the key in the ignition , turn it so all the lights come on and then leave it for 6 minutes while the transponder in the key resets all the immobilser etc. worked for me, might be worth you triying?

[ronaldo60]

yep tried that, no joy, even gave it more time to make up for my cruel injury to the poor car, still no joy, engine just turns, never starts and key does not operate doors or trunk.

thanks for the fast feed back.

Ronaldo,

[ColinBarber]

Does every thing else work on the car?

When you say the immobiliser is not responding I take it you me the security light doesn't go out when you put the key in the ignition?

[alanliverpool]

Does every thing else work on the car?

When you say the immobiliser is not responding I take it you me the security light doesn't go out when you put the key in the ignition?

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MY INTERIOR LIGHT MY STERRING WHEEL AND KEY FOB WOULDNT WORK ON MINE,TURNED OUT TO BE 10 AMP FUSE IN THE MAIN FUSE BOX UNDER THE BONNET,I CHANGED IT AND THEY ALL CAME BACK ON,DONT KNOW WETHER YOURS MIGHT BE SAME SORT OF PROB

[Dave M]

Does anything else work in the car? Things like the radio, windows, mirrors, aircon & memory seats?

Also, which fuses blew and have any of them blown again since you replaced them?

[ronaldo60]

Does anything else work in the car?  Things like the radio, windows, mirrors, aircon & memory seats?

Also, which fuses blew and have any of them blown again since you replaced them?

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everything works that has a fuse, i had to steal some non essential fuses from the head lights etc as it was after the shops closed on saturday....

the horn fuse, ecb2 fuse, plus 2 others i cant remember now, were blown.

none have re-blown since being replaced.

The current symptoms are that the engine cranks just fine,

The red light indicating the immobiliser is set does not go out

The key (both sets) will not function to lock/unlock the doors or boot.

All other electrics appear to work fine, windows int lights, turn signals etc

Thanks for the feedback,

Ronaldo.

[Dave M]

It sounds as if one or more of the ECMs have been damaged by having the polarity reversed. Often they have voltage regulators inside them which effectively act as a dead short when the polarity is reversed, which is what causes the fuses to blow. You can normally tell if a voltage regulator has gone by the fact that it will be charred black and smell bad. If you're lucky the regulator will have blown the fuse before the rest of the ECM is damaged. If you're really lucky, it will blow the fuse before it gets damaged too.

Unfortunately you'd need to take the affected ECM apart to see if there was any damage - I suspect Lexus would just replace the entire module though.

Are there any warning lights on the dashboard when you try to start the engine?

It's probably worth seeing if you can get a friendly lexus engineer to come out with a handheld tester, they might be able to read some fault codes and get a better idea of what's going on.

[ronaldo60]

Thanks dave M and all for the feedback. I have a local toyota guy checking it out tomorrow. I had hoped to be able to resolve this stupid mistake with less pain to my pocket. I was told today that sometimes you have to leave the key in the ignition on position for 30 minutes to get it to reprogram, that was the kind of miracle i was hoping for. Guy said it was in a (toyota) service bulletin.

This is a great forum, thanks everyone.

Ronaldo,

[Tron20]

Just one quick question, don't mean to be silly, but why were you jump starting a lexus anyway? and why backwards?

I've never really paid attention to the immobiliser warning like on a mk1 gs300 yet alone a mk2, but i know if you run the engine for a short period of time, it doesn't burn all the fuel off, then when you restart it, it throws in more fuel flooding the engine, happened on my brothers a couple of times. I wouldn't have thought that toyota would have designed the immobiliser to allow the engine to crank whilst the immobiliser was on, but i don't know

[Dave M]

Hope you get it sorted without too much expense. Let us know what happens!