2006 LS430 - Key and alarm issues!

DomTurner · February 10, 2023

So this afternoon I noticed my main key's buttons weren't doing anything so I couldn't lock/unlock the car. Fine I thought and attempted to use the physical key (never needed to use them before), only the master key's casing is broken and so I couldn't access the physical key. So I went to get my spare key which weirdly enough ALSO didn't unlock or lock the car remotely... I was, however, able to get the physical key into a position where it could enter the driver's door - however this just set the alarm off... No matter how many times I turned the key from Lock to Unlock, the alarm doesn't go off until it is in a locked state and the key is out of the keyhole and after about 10 seconds the alarm finishes (only with a locked car however).

I have also noticed that no lights are flashing inside for the smart access/alarm system: shown here with the red arrow:

The strangest thing is I can turn the ignition on and even start the engine but the alarm will sound constantly... I cannot see any error warnings on the dash or anything but I cannot dig further really as the entire estate has been looking at me funny! It seems I can't really use my car at all at the moment.

I Have tried new batteries in two of the keys but all 3 that I have are not working.

Any help is appreciated!

Malc1 · February 10, 2023

the problem might be with the main Battery in the engine compartment ..........

the keys need to read from that too

Malc

DomTurner · February 10, 2023

16 minutes ago, Malc1 said:

the problem might be with the main battery in the engine compartment ..........

the keys need to read from that too

Malc

Thanks, it did go through my mind but with the car turning over and starting fine as well as the fact i’ve had no other signs before now, I dismissed it - I will look into that and see if I can get it tested, will just have to drive with the alarm going off!

steve2006 · February 10, 2023

The first, easiest and cheapest option is to remove the Battery negative lead, leave it 15 minutes then reconnect and try the car again.

There have been reports of corroded terminals in the boot causing sudden failure of the Smart and security systems but try the above first.

steve2006 · February 10, 2023

I think the alarm horn is located under the Battery tray, just pull off one connection to shut it up.

BTW I noticed your picture shows a LHD model?

DomTurner · February 10, 2023

8 minutes ago, steve2006 said:

The first, easiest and cheapest option is to remove the battery negative lead, leave it 15 minutes then reconnect and try the car again.

There have been reports of corroded terminals in the boot causing sudden failure of the Smart and security systems but try the above first.

Thanks, i will also try this.

Funny you should mention the corroded terminals in the boot as i read this could make it so the button on the boot itself could fail - it has never worked since i had the car, i’ve always had to use the key or the trunk release in the front.

DomTurner · February 10, 2023

1 minute ago, steve2006 said:

I think the alarm horn is located under the battery tray, just pull off one connection to shut it up.

BTW I noticed your picture shows a LHD model?

that was just an example image as i’m not at my car at the moment and was the only one after a quick search that showed the lights i was mentioning.

steve2006 · February 10, 2023

1 minute ago, DomTurner said:

that was just an example image as i’m not at my car at the moment and was the only one after a quick search that showed the lights i was mentioning.

I thought it may have been but didn’t want to confuse locations between LHD and RHD 😀

steve2006 · February 10, 2023

Just another thought, was the green Smart indicator flashing prior to this issue?

DomTurner · February 10, 2023

Just now, steve2006 said:

Just another thought, was the green Smart indicator flashing prior to this issue?

yes i have always noticed it flashing green and i was in and out of my car a few times today using the keyless entry system until this happened

lex - eleven · February 10, 2023

I'm not electrickery minded but the button under the dash to turn the smart system off hasn't been touched?

cruisermark · February 10, 2023

Hi Dom

Did this happen in a new location??

The exact "glitch" happened to me aswell in a waitrose car park - never repeated itself though.

DomTurner · February 10, 2023

Hi everyone, firstly thank you for all your help and suggestions.

As the engine runs and allows me into drive, I drove the car into my work's car park so I could work on it without the alarms annoying anyone. Bit embarrassing as the alarm was running for a few minutes on the way - I promise it's not stolen!

Half way into the journey the alarm stopped and everything seemed normal, no errors and no flashing lights. Got into the works car park and turned off the engine, took the key out and instantly noticed that the light for the SMART access had returned to flashing green and the normal alarm light was flashing red, just like before. I could shut the door and lock it with the black button and after a few seconds could unlock it using the keyless function (hand behind the door handle sensor)! The system seems like it has returned to normal and the main key works to lock and unlock, as well as working in the ignition.

I will get a lift into work tomorrow and test it in the morning along with my other keys to see if it truly has fixed itself but for now it's good news!

I am guessing the car needed the key in the ignition for a minute or two to recognise it and disable the alarm and I must have took the key out too fast when testing before - if I had known the alarm would eventually quiet down I would've done it on the drive but it's a bit awkward with the curtain twitchers watching!

Will update everyone once I know for sure.

A slightly related point - my sisters E46 BMW 320i has decided to refuse to lock/unlock remotely when parked near the house but has been fine elsewhere - this only started today as well? Strange!

Malc1 · February 11, 2023

14 hours ago, DomTurner said:

A slightly related point - my sisters E46 BMW 320i has decided to refuse to lock/unlock remotely when parked near the house but has been fine elsewhere - this only started today as well? Strange!

needs scrapping then .... . not worth messing around with ..... it's a BMW NOT ......... a brilliant Lexus

Malc

Malc1 · February 11, 2023

14 hours ago, DomTurner said:

but for now it's good news!

and there we are .. didn't know the Ls430 was " self-healing " like the Ls400 . but hey, you now have won that battle

well done

Malc

steve2006 · February 11, 2023

The system uses a “rolling code” method so basically each time you press a button on the fob the security code is changed and synchronised to the car. If for some reason the fob and car codes no longer match you then get the problem you had, basically the fob talks in one language and the car another so they cannot understand each other, the car becomes annoyed and sets the alarm off in protest.

Leaving the fob in the ignition switch turned to ignition for 7-10 minutes allows the 2 to reestablish communications which appears to be the case with yours.

DomTurner · February 11, 2023

Just now, Malc1 said:

needs scrapping then .... . not worth messing around with ..... it's a BMW NOT ......... a brilliant Lexus

Malc

this lexus is becoming less and less “brilliant”.

Got a lift to work early this morning and the car is working perfectly fine, keyless instantly worked as the puddle lights came on when i was near and i could unlock it etc… started it up and let it get up to temp and then parked up, ready for me after work.

Finished work and come out to my car - everything is perfect again.

Pull onto my drive, switch the engine off and as soon as i shut my door I heard a locking/mechanical noise from the rear of the car. Same thing as yesterday is happening… I cannot unlock or lock with the key and i’m guessing the alarm will go off if i try and open the door…

wtf is happening.

Malc1 · February 11, 2023

is it time to refer to a competent Auto Electrician maybe ?

unless Steve or someone with a good knowledge of these beautiful cars can think of summat else !

Malc

steve2006 · February 11, 2023

Here is something I’ve found which may be worth checking.

Borrowed from CL, take a look at posts 32/33 and 58/59

https://www.clublexus.com/forums/ls-3rd-gen-2001-2006/755328-2004-ls430-keyless-entry-and-smart-key-suddenly-stopped-working-2.html

Could you be more specific regarding the location of the noise from the rear of the car, just wondering if you have the common issue with one of the rear door lock motors, which fail to complete the full lock/unlock sequence resulting in a confused ECU not knowing if a door is locked or unlocked.

DomTurner · February 11, 2023

okay another update, this sounds stupid but...

i mentioned yesterday that my sisters e46 isnt locking/unlocking with the key from the house... tried it again this morning and same result. she moved it 10 feet down the road and it's working fine... move it back and its no longer working

Malc1 · February 11, 2023

5 minutes ago, DomTurner said:

move it back and its no longer working

OK I now understand better . some years ago I had exactly this problem in a local car park with another car AND it was the signal from a close by MAST that was causing me these problems ..... is it something like that possibly ?

Malc

rich1068 · February 11, 2023

There's about a 500 yard spot on Ecclesall Road in Sheffield where neither my old IS300 or RX400h would lock or unlock using the remote.

DomTurner · February 11, 2023

32 minutes ago, steve2006 said:

Here is something I’ve found which may be worth checking.

Borrowed from CL, take a look at posts 32/33 and 58/59

https://www.clublexus.com/forums/ls-3rd-gen-2001-2006/755328-2004-ls430-keyless-entry-and-smart-key-suddenly-stopped-working-2.html

Could you be more specific regarding the location of the noise from the rear of the car, just wondering if you have the common issue with one of the rear door lock motors, which fail to complete the full lock/unlock sequence resulting in a confused ECU not knowing if a door is locked or unlocked.

thanks for the info.

the noise sounds more like it's coming from the boot, almost like when it self closes just a bit deeper sounding. i need to disconnect the alarm horn before investigating further though.

DomTurner · February 11, 2023

1 minute ago, rich1068 said:

There's about a 500 yard spot on Ecclesall Road in Sheffield where neither my old IS300 or RX400h would lock or unlock using the remote.

very strange! i'm trying to think if there's anything in the house that can be causing this but it was working fine one minute and then f***ed the next. perhaps a neighbour...

DomTurner · February 11, 2023

Has to be some sort of interference or something, next door's car is doing the same! Power off in the house and still happening so unsure what to do next! I'll figure something out...