2005 RX300 key programming

[sorcerer]

Bought our first ever Lexus, a 2005 RX300, about four weeks ago and it came with two keys, or more correctly, I suppose I could say one and a half - a grey one that works as it should and a black one with a broken plastic case that had been taped up very close to the blade and is completely useless.

I found a key on eBay for a couple of quid that had an empty case and an uncut blade, the idea being to transfer my own electronics into it from the broken key and then have the blade cut at my local locksmiths. It didn't cut very well and can take a bit of force to get it into the lock barrel so I won't be using it. It was worth a punt for a few quid but it's now a failed experiment. Just by chance I found a thread on here a couple of days ago about a guy on eBay who supplies the blanks and cuts them to your own key code and/or by photograph, so I've ordered one from him.

Anyway, on to my real problem. The LED on the broken black key wasn't lighting up when any button was pressed so I changed the Battery and now, any button press will result in the LED indicator lighting up as it should. However, it doesn't do anything else - doesn't lock/unlock any of the doors or tailgate and won't start the car. Of course, the Battery may have been dead for months, even years, but I thought the transponder was non-volatile, i.e., once the key was programmed it was programmed and would remain so until overwritten.

Do you think there's a problem with the transponder or is it really just simply that the Battery was dead for too long and the programming has been lost due to lack of power?

 

[sorcerer]

Well, with 63 views but no replies, maybe no-one knows the answer to this one, so let's assume that the transponder isn't faulty but does need reprogramming - how do I do that? I could have sworn I saw a thread about it on here the other day but can I find it again? No I can't, so any help gratefully received

[ChrisKaye]

Just a crazy suggestion, put your non-working remote key in the ignition and turn it to just before the starter kicks in and ignition is on.

Then try pressing the lock and unlock buttons in turn for a few cycles.

This seems to do the trick on my older Toyotas with factory fit alarms.

From memory it has something to do with 'rolling' codes that need to resync before the buttons work again.

As long as the red LED lights up, it would be uncommon for it to pack up altogether!!

Fingers crossed!

Sent from my Iphone using Tapatalk

[sorcerer]

Ok, curioser and curioser as Alice would say!

I tried your suggestion Chris (thanks very much) but sadly it didn't work. I found a Youtube video done by a guy called 'speedkar99' in which he was programming a key for some other model of Lexus, so I contacted him and asked if that same procedure would work on a 2005 RX300. He said no, but to follow the instructions in this video here for the RX300. The first part of the video deals with programming the immobiliser and the latter part with programming the remote locking.

If I insert my old broken key into the steering lock without any electronics the car cranks but will not fire up. When I try it with my new key with transponder, the car fires up and runs as expected, thereby proving that the immobiliser part is working correctly.

The procedure for programming the remote locking is as follows:

1. Start with all doors closed
2. Open driver's door
3. Insert key, remove key
4. Insert key, remove key
5. Close door, open door
6. Close door, open door
7. Insert key, close door
8. Turn key to 'On' position* then off
9. Remove key
10. The locks will now cycle to indicate that you're in programming mode
11. Hold lock and unlock buttons down together for 1.5 seconds then release
12. Press any button on the key and the locks will now cycle to indicate programming has been successful
13. Exit programming mode by opening door

*At step No.8 in the video, he turns the key on and there's a beep before he turns it off again - mine does NOT beep. However, at Step No.10, my locks DO cycle, which would sort of imply that all previous steps have completed successfully - wouldn't it? Unfortunately, after holding down the lock/unlock buttons simultaneously (Step 11), my locks do NOT cycle as they should (Step 12).

What does that all mean and what can I do now?

[The-Acre]

I feel your pain on this one!  I had the same problem on an LS400.  I bought a used key, had a new blank cut and went through the programming process.  I tried several times, was about to give up but on the last attempt it worked.  I don't know why but I can only assume it was my timings. Apparently you can't "un programme" by constantly trying so maybe give it a few more goes?

[sorcerer]

Well I'll go t'foot of our stairs, as my dear departed Granny used to say!!

Phil, after reading your post I thought I'd have a few more goes and it worked first time! It must have been my timings - I think I was holding the lock/unlock buttons longer than the 1.5 seconds in Step 11. I suppose opening/closing doors can take different amounts of time each time you do it but "1.5 seconds" is a bit exact and it must be critical.

Cheers mate

[The-Acre]

Excellent, and isn't it a great feeling when it works!

[Prince Bob]

I wish I knew about the key programming a couple of months ago, I ended up taking the car to an auto locksmith who reprogrammed an existing key and cut and programmed a brand new key while I waited (35 mins) for £100! 

[sorcerer]

44 minutes ago, Prince Bob said:

I wish I knew about the key programming a couple of months ago, I ended up taking the car to an auto locksmith who reprogrammed an existing key and cut and programmed a brand new key while I waited (35 mins) for £100! 

Ouch!!