Remote Keyless Locking System Not Working Anymore...

[topgun129]

Hi,

After many years of using the remote keyless locking system in my 93 LS400, now for some reason it no longer is working. I have changed the key battery but that did not do it either. I am simply not getting a response from the car when pressing the button on my key. If I use the manual switch on near my windows the car locks fine and when I use the key holes on the doors to unlock or lock the car everything goes smooth.

I had in the past problems where the Remote Keyless locking system would not work for a few days but then it would start working again, but now it seems like a no-go! :(

Any ideas guys and gals? I believe the fuse is #10 but my dome light which is on the same fuse (and all other lights) are working so I don't thing the fuse is a problem.

Thanks in advance for your tips!

[VBdenny]

just make sure the OFF/ON switch for the remote on the dash was accidently turned to off.

[topgun129]

Hi,

No, the button has always been in the on position so that we can rule out.

Thanks!

[topgun129]

Any other ideas?

I was reading on the forums that there is a way to reset the locking system on LS400s (basically a bunch of steps of closing and opening the door intertwined with unlocking and locking the car).

I'm still puzzled as to what has caused this problem since everything was working fine recently.

Thanks!

[1990LS400]

If the 93 LS keyless entry system is like the one on the 90 LS I had for many years, there is a ROM chip in the receiver on the driver's side of the trunk behind the trim that can vibrate loose. Try removing and reseating the ROM chip.

The ROM chip in my 90 LS vibrated lose causing the keyless entry to work intermittently for a number of years -- probably related to the dealer replacing the ROM chip and all the keys under warranty trying to find a frequency that didn't conflict with security systems in shopping centers near where I lived.

When I sold the car in 2003, the new owner reseated the ROM chip which fixed the problem. Here is a thread where he (Toby / ylekiot1) explained how to do it: http://us.lexusownersclub.com/forums/index...&hl=keyless

[VBdenny]

One of my keys, the remote doesn't work at all. The other works fine now that I cleaned it out. I disassembled it and cleaned the parts with a fine brush, popped in a new battery, and with the lint and dirt gone, it works fine. On the key that doesn't remote, the guts were different? not sure why

[topgun129]

Hi,

Thank you everybody for your help so far.

@1990LS400 - I tried what you recommended but it was a no-go.

@VBdenny - I also tried what you recommended but it was a no-go.

Basically after doing some more diagnostics I have come to the conclusion the key transmitter is faulty.

So now my question is - What is the cheapest what to fix the key or get a replacement?

Thanks!

[92LS400D-town]

Hi,

Thank you everybody for your help so far.

@1990LS400 - I tried what you recommended but it was a no-go.

@VBdenny - I also tried what you recommended but it was a no-go.

Basically after doing some more diagnostics I have come to the conclusion the key transmitter is faulty.

So now my question is - What is the cheapest what to fix the key or get a replacement?

Thanks!

Just a heads up, I had the exact same problem and turns out the key had trash in it. I took the key cover off and sprayed electrical cleaner in the key with the battery removed then blew it out. Once dry put the battery & cap back on. Works like a charm!