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2004 LS430: keyless entry (and smart key) suddenly stopped working

Old 09-01-14, 02:52 PM
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mikevanle
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Default 2004 LS430: keyless entry (and smart key) suddenly stopped working

Hello, I realized the keyless entry and smart key stopped working this morning out of the blue. Went up to the car and it wouldn't detect I was near. Then when I took the keys out to unlock it, nothing happened. I've been resorting to pulling they actual metal key out of the key and unlocking the key that way.

The battery of the remote was good, but I changed it anyways without success. I used another spare key and it was doing the same thing. Is there a fuse or ECU or something I can check?

Thanks for any help.
Old 09-01-14, 04:45 PM
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SQuester
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Make sure the button to activate the smart key is on. It's underneath the dash, drivers side. If you were sitting in the seat in a driving position, the buttons(one for smart key, one for tire pressure reset) are directly above where your right shin would be.
Old 09-01-14, 04:45 PM
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fensterlip
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There is a fuse for this, yes. Don't remember location and this could be the problem. The key could require re-synching with the car too. As I recall, it is done by putting the key in the ignition for a few minutes, position 0 or 1. There have been posts on this worth searching for.
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Old 09-01-14, 06:24 PM
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Originally Posted by fensterlip
There is a fuse for this, yes. Don't remember location and this could be the problem. The key could require re-synching with the car too. As I recall, it is done by putting the key in the ignition for a few minutes, position 0 or 1. There have been posts on this worth searching for.
Here's a drawing showing fuse locations...
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Old 09-01-14, 06:31 PM
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mikevanle
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Originally Posted by SQuester
Make sure the button to activate the smart key is on. It's underneath the dash, drivers side. If you were sitting in the seat in a driving position, the buttons(one for smart key, one for tire pressure reset) are directly above where your right shin would be.
The button underneath the driver's right knee is normal. The real issue (and I think caused the Smart key to not work as a byproduct) is the keyless is not working. The car will not lock/unlock/open trunk with the key fob. I tried 2 other keys I have (1 master and one valet), but they also do not work.

I have checked the fuses in the engine and in the trunk (left side). I will continue to check other fuses tomorrow.

I went through the steps of programming a new key as described here, http://blog.keylessentryremotefob.co...ob-remote.html and the door locks cycle themselves at step 11. But when I went to hold lock/unlock on the key, nothing happens.
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Old 09-01-14, 07:31 PM
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Are you sure the battery is good? Inside the remote. You should see a red light when you press the lock or unlock.
Old 09-01-14, 07:35 PM
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If the button underneath the driver's right knee is normal, you should see the "SMART" green light on the dashboard flashing (see yellow pointer on picture below). Another thing you can try is to reset the ECU by disconnecting the battery for about a minute, and then reconnect it. Sometimes this trick resolves some strange electronic problems - doesn't hurt to try...


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Old 09-02-14, 07:50 AM
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I confirmed the key battery is good. I've also changed it and tried the spare keys without success.

I also confirm the green SMART light is blinking. I also disconnected the battery for some time and reconnected it without success.

I've also checked the fuses in the engine, drivers kickstand, passenger kickstand, and trunk.
Old 09-02-14, 10:35 AM
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Are you able to lock and unlock the doors with the physical switches on the inside of the door? Just want to confirm that the lock actuators are functioning properly.
Old 09-02-14, 12:24 PM
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Originally Posted by rkw77080
Are you able to lock and unlock the doors with the physical switches on the inside of the door? Just want to confirm that the lock actuators are functioning properly.
Yes, they work fine.

As of now, I've scheduled an appointment with Lexus for this Saturday. Hopefully it won't cost too much for them to investigate the issue, and then tell me I need to replace a $2,000 part or something. I'm still trying to search the internet to find a solution in the meantime.
Old 09-02-14, 01:35 PM
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Do you have your manual? I would check fuses 23 and 34 - 39. Passenger side kick panel if you have not already.

Edit. And fuse 5 at the drivers side kick.

Last edited by Lavrishevo; 09-02-14 at 01:38 PM.
Old 09-02-14, 02:02 PM
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Other than unable to lock and unlock doors, were you able to get you fob to perform other functions like, open trunk? start engine (with fob in pocket)? Open windows and sunroof (press and hold "Unlock" button for 3 seconds)? Can you activate the "Panic" function? Did you get the "Key Not Detected" message on the instrument display? I have a shop manual for the 2004 LS430 and will try to read up on it for you tonight.
Old 09-02-14, 06:09 PM
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Originally Posted by rkw77080
Other than unable to lock and unlock doors, were you able to get you fob to perform other functions like, open trunk? No, I cannot open the trunk using the Trunk button on the remote. I have to open the trunk with the switch inside the car or extending the metal section of the key and open the trunk that way
start engine (with fob in pocket)?No, the engine will only start if I insert the key into the ignition slow
Open windows and sunroof (press and hold "Unlock" button for 3 seconds)?No, it seems none of the buttons on the remote is doing anything for the car
Can you activate the "Panic" function?No, refer to previous answer
Did you get the "Key Not Detected" message on the instrument display?Yes, I get the key not detected message on the dash when I try to turn the ignition without the key inserted
I have a shop manual for the 2004 LS430 and will try to read up on it for you tonight.
See my responses above
Old 09-02-14, 06:11 PM
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Originally Posted by Lavrishevo
Do you have your manual? I would check fuses 23 and 34 - 39. Passenger side kick panel if you have not already.

Edit. And fuse 5 at the drivers side kick.
Yes, I have checked the fuses. This "thing" literally happened overnight. The previous night (Sunday) it worked fine then when I went to my car Monday morning, I noticed this problem. There was light rain the previous night and I normally parked my car outside. It's not anything new, but it's worth mentioning I suppose.
Old 09-02-14, 06:50 PM
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Alright, here's the inspection procedure from the shop manual (refer to picture below)...
Step 1: Inspect fuses. Check MPX-IG and AM1 in the driver side J/B; and D DOOR and MPX-B1 in the passenger J/B. I believe you have checked these already.
Step 2: Inspect relay. The relay is located on the right side of the driver side J/B. Remove the relay and confirm terminals 3 and 5 is open (when no power is applied to terminals 1 and 2); then apply 12V power to terminals 1 and 2 and confirm terminals 3 and 5 is closed (short-circuit).


Last edited by rkw77080; 09-02-14 at 06:54 PM.

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