So my 92 sc400 remote key had a broken key ring piece and couldn't be attached to keys I lost it unsurprisingly, anyways shoved my window dow n obv set the alarm off when i pulled passenger door lock to get keys made, put it back n cycled the locks but still no crank. no dash lights, shift lock on, no brake boosting etc. i have a good fuel pump, good relay (can start with a paper clip) and the key turns both the doors and the ignition. tried the battery/key indiana jones trick and pulling theft fuses, i'm on a brand new optima battery. any other ideas?

 

Hello,

What kind of a remote was it?

The thing is that those cars didn't come with the immobilizer as far as I am aware, depends on what kind of key you have. With that, even if you do have an immobilizer system, it doesn't lock the Starter, it disables Ignition, which makes me wonder if you have an aftermarket system installed somewhere in the car, which doesn't function without disarming the system with either factory or aftermarket remote.

Start by inspecting the interior for any extraneous switches, aftermarket wiring, splices, etc., then take the covers off behind the steering wheel and inspect the wiring around Ignition Switch, that is where the Starter wire is located that most of the installers use to splice the alarm system. If you will find it, I would strongly suggest getting rid of it, you never know who installed it and what other "surprises" it has in stock, not to mention that it is borderline useless without a remote.

Hope this helps and best of luck!

 

it was a stock lexus key with the little grey buttons in the bottom corner. i will check but im fairly sure it's the stock alarm... not particularly savvy with diagrams but as far as i know it provides ignition ground so if i splice wtv wire to a body ground or some other constant ground wire would that practically disable it

 

Here is a snippet from the Owners Manual for your car that shows the factory key. This generation came with a pretty unique key with only one button on the side to lock and unlock the car, they quickly got rid of it though unfortunately..

Not sure what you mean.. Which wire do you splice to Ground? Factory system is designed to disable all engine controls, including Ignition and Fuel Injectors, and it does so by not supplying the needed signals (disabling the ECU, which is a lot harder to go around), not by cutting the Ground supply. If you can bypass the alarm system by shorting something to Ground, then either some OEM wire got damaged, or it is not an OEM system, you will need to find where said wire goes and get rid of that system.

Hope this helps and best of luck!

 

I have a ‘92 (albeit a 300) and the original key fob has a small pci board in the housing. It only has a single button but mine only opens the locks; I don’t ever remember it locking the doors, though.

The car being so old, I decided to avoid using the button to open the door so not to “wear out” the actuator and using the key in the lock is adequate.

A multi button fob (take a picture and post it) is likely aftermarket….

 

Had the no start problem myself, 1st time locking the car, had to go under the car to activate the starter to get the car home. Could not deactivate the alarm system by unlocking the door. There's an electrical connection attached to the door lock cylinder, mine was broken off. This connection is what disconnects the alarm. I had to go in the door panel and retrieve the broken electrical connector and turn it by hand to the unlock position to deactivate the alarm. I already ordered a new connector. Meanwhile I left the door lock cylinder connection out of the door just is case.

 

The stock alarm has a disarm wire that sends a ground pulse to disarm it, i'm wondering if it has to be a certain length or if i can just ground it and permanently be "disarming" it.

It was not a fob at least not in the modern sense just a master key with grey buttons.

 

i already reattached that on my lock tho and had someone hold it in place so i could cycle the locks

 

Whole problem started when i got into the car by regulator to get new keys made, just pulled the neg cable to shut it up until i cycled the locks but lo n behold they cycle and the alarm stays on

 

If you don't need that alarm at all, it would be a lot wiser to simply pull it out completely, you never know how many hidden surprises are still in it waiting to be discovered. Just find all the aftermarket wiring and splice back what was cut to integrate it.

Hope this helps and best of luck!

 

stock = OEM, came on the car. there's no aftermarket anything on the car save for some headlights and a cai but imma splice the wire in a few days when i got time and let y'all know how it goes