beels1

I apologize in advance for starting yet another Key thread, but after fighting this for 2 days, and reading everything there is on the internet about key programming, I am about out of DIY options.

My saga:
2003 LS430. I want to add 2 extra Master Keys. I have 2 shells cut to my keycode and paired them with 2 used OEM remote modules, FCC ID: HYQ12BBK. I bought a Mini-VCI cable (FW 2.0.4) and was able to quickly and easily use Techstream 12.00.127 to perform the Immobilizer code registration on both new keys, however, when I try to perform the Wireless code registration, it always times out. There is never any response from Techstream or the vehicle when I hit Lock & Unlock simultaneously, followed by the Lock or Unlock. I have tried various combinations of changing the timing interval slightly and hitting the Unlock an instant prior to the Lock, as one poster suggested.
Techstream does inform me I have 2 registered keys and 2 available slots.
Also, when I go into the Wireless Diagnostic, I can get the car to beep once when I hit the new remotes, so it seems like the car is getting a recognizable signal from them.

OK, so now on to plan B -- Manual Process. Using the "insert/remove key twice, close/open door twice, insert/remove key, close/open twice, insert, close, ignition on" process, I am able to easily get the car in either ADD or Confirmation mode. But when I do the remote button presses, I always get the double lock/unlock, indicating the registration has failed again. Confirmation mode also confirms I have only 2 keys registered, not that it matters.

Other possibly related strangeness is that in Techstream, I am unable to Customize the Door Lock behavior. I tried to set the Theft Deterrent ECU so that one remote press unlocks all doors, but it just won't "take." Techstream says it is writing the config, then the screen returns showing it has not changed. As a test, I made this same change on another vehicle, a 2010 ES350 with no issue. So it seems like the cable is functioning, plus I was able to use it to perform the Immobilizer programming on the LS430.

Any thoughts from the experts? Is my vehicle somehow "locked" so it won't take any wireless key registrations or door lock customization?

rkw77080

Here are the pages from the repair manual. Please give it another thorough read.

beels1

Thanks rkw. I saw these instructions from a post of yours awhile ago, and I have read through the procedure several times. I make it to the confirmation of the Add mode (Lock/Unlock once), but that's it. No response after the remote button press sequence, except the double Lock/Unlock..

Questions I have:
The doc talks about the Add mode being for adding "newly" recognized codes. I wonder if this means there could be a time limit between the time you register with the immobilizer and when you perform the wireless registration procedure? I doubt it, as I believe keys are registered with two separate systems/ECUs.

Is there a preferred sequence of the 2 registration procedures, such as maybe you should perform the wireless pairing before the immobilizer registration? I've never seen a reference to that though.

Is it possible the frequency of my remote units is incompatible for wireless remote access, yet still compatible with the immobilizer? I'm starting to lean this way, because I have tried 3 different used OEM remotes, plus a known good 4th remote that I use on another car. All are FCC ID HYQ12BBK, which should be correct for this year and model.

rkw77080

I have not performed the procedures personally, so I cannot offer any advice - sorry. Here are some more pages on the Wireless door lock system. Hope there's some useful information in there somewhere.

beels1

Just tried for another hour or so, using both the manual switch mode and Techstream. Get double Lock/Unlock when attempting manual mode, and no response using Techstream. Now I'm thinking my Theft Deterrent ECU is faulty and/or stuck in some kind of Read-Only state. That would also explain why I can't change any other settings for this ECU.

beels1

I figured it was time for an update to this issue.

Next thing I tried was to pair these 2 extra Master Keys to a 2002 SC that uses the same FCC ID. I was able to easily pair both new keys to the SC in seconds using Techstream, so determined there is no issue with the functioning of key remotes themselves.

Next I took the car to a locksmith to see if he could program the keys. He just used the same "insert/remove key twice, close/open door twice, insert/remove key, close/open twice, insert, close, ignition on" process that I used -- also unsuccessfully. He said they have a tool they can hook up, but it won't work on this car (??) His search revealed another FCC ID for that model year, and he tried one of that version key, but it also wouldn't program. (The dealer had previously confirmed my correct key part number using my VIN, so my keys are correct, unless perhaps a previous owner had changed out the ECU.)

So then I admitted defeat and took the LS to the dealer. They said they would program my keys for $50. OK, fine. After an hour, they brought the car back (washed, yay) and said they can't program them. They also followed the above process. I said don't you have a Techstream device you hook up to do the key programming? "No, it doesn't work on that car." Huh?

Next they tried to make the Door Lock customizations that I wanted. A guy brings out a Mongoose with a Techstream laptop, and, just like my experience, none of the door lock settings would persist or "take." He said he's never seen that before, but sometimes there are options listed you can't change on certain cars. (Agreed, but these are simple, verifiable options, such as open all doors with one remote button press.)

So I said, "why aren't they able to program my remote keys?" The service writer said it must be because I have pre-owned keys: "there is something about used keys, and I've seen this problem before. Maybe it's because they have been programmed to another car." (Wrong. These aren't Smart Keys, and I programmed them to an SC in seconds.) "If you buy one of our keys, I'm sure they can get it to work." I said, "OK, fine. I will buy your key for $200+$50 programming, but only if you can get it to work with my car." They put me in a loaner and off I went.... Not hopeful, because at this point, I'm virtually certain this is a Theft Deterrent ECU issue, as I have believed for a week.

Just returned from the dealer this afternoon. I went back into the shop and spoke to one of their Master techs who was working on the car. He said there is something wrong with the Theft Deterrent ECU (surprise!) and the next option is to attempt a re-seed. He said 50-50 chance it will either work, or I will have no wireless keys working. He has seen this exact situation only once before on this model, years ago, and the re-seed was successful. I am a gambler and a perfectionist, so I said "do it" and left. Service Manager thinks I have lost my mind since I do have 2 working keys now.

Fingers crossed. If unsuccessful, I guess the next step will be to live with no remote access (I can't), or replace the ECU...unfortunately it's located under the dash (yuck).

beels1

Update: The re-seed was not successful, but they did not lose the registrations for the 2 keys that are currently programmed. So I assume this means they were not even able to wipe the ECU - totally in a read-only mode. I guess if I want to continue to pursue this, I need to repair or replace that ECU.

rkw77080

The Immobilize system consists of a Theft Deterrent ECU and a Transponder Key ECU. The two ECUs communicate with each other via multiplex bus.



Each of the 4 doors is equipped with its own Door Control ECU.



Communication for the Wireless Door Lock System is a bit more complicated. Instead of communicating with one another, the 4 Door Control ECUs are connected in series. That is, the Transponder Computer communicates with the Driver Door Control ECU, it then communicates with the Rear Left Door Control ECU, then Rear Right Door Control ECU, then Front Passenger Door Control ECU. Any problem along this daisy-chain will compromise the communication to the remaining door lock ECUs downstream. I suspect this may be the case for you, whereas, the new keys cannot be registered to one or more ECU along the communication chain and therefore the process was halted.

beels1

Thanks rkw, I was hoping you would weigh in! All my problems seem to be associated with the Theft Deterrent ECU. The Immobilizer ECU seems to be functioning properly as I am able to change settings associated with it, such as registering keys with the Immobilizer, and changing the telescopic steering wheel settings.

You mentioned that it is the Transponder ECU that communicates with the daisy-chained individual door control ECUs, but since I am able to successfully register keys with the Immobilizer, does that not imply that the Transponder ECU, the daisy chain communications, and all the individual door lock ECUs are working properly?

rkw77080

On second thought, I think you're correct. If you can "wirelessly" lock/unlock all 4 doors, the problem does not seem to be with the multiplex communication bus (One ECU picks up the wireless signal, then communicates the same to the other 3 ECUs).

beels1

Thanks rkw, So...do you think I should try to replace that Theft Deterrent ECU? If so, do you know the part number and how to get to it? I understand it is somewhere in the center dash area. Not sure if you can get to it through the glove box or not.

Can I just pop in a used one all will be well, or is there some magic needed to pair it to the rest of that system?

rkw77080

Here are the sketches I found for the Theft Deterrent ECU. I was not able to find anything on part number or removal. Sorry!

beels1

OK, just to close this off, in case it helps someone else. I bent over and had the dealer replace the Theft Deterrent ECU (89730-50092). So now I can change the door lock settings and register the master key remote functions!

The dash had to be removed to gain access to the misbehaving ECU, which resides near the passenger airbag area, so I didn't want to attempt it myself. As well, I didn't want to risk having a Lexus aftermarket repair shop make this repair with a used part, due to the labor involved, and I also didn't know if some dealer magic, or permissions, were required to integrate the new ECU to the rest of the system, so I went full-on dealer service with a brand new CPU.

The dealer said there were none of these parts in the Lexus USA system and it had to come from Japan (even though I see several buying options on the internet), so I'm thinking this must be a very rare component failure. Of course many people could have this issue and never know it if they aren't messing with programming new keys and door lock functions. In fact, this could easily have been a Day 1 issue with this car.

I was expecting to see some obvious physical damage such as bulging capacitors, burn marks on the PCB, water damage, etc, but there is nothing out of the ordinary inside. Everything looks great. One of the reasons I went forward with replacing the ECU is I thought any PCB damage, such as caused by leaking caps, would continue to get worse until it eventually caused a total failure of this module, however after looking at it, I doubt it would have gotten any worse. In a way, though, this makes me feel better then seeing some failed capacitors, because then I would worry about the other capacitors in the many other ECUs throughout the car.

karsonas

so i have 2 ls430 cars

first ls430 had two masters keys works perfectly all good
second ls430 has 1 master key and 1 valet key smart function does not work (last owner said that is working good but lost 2nd master key)..

soo i tried to program master keys with techstream, autel, chiken dance you mention but without luck

BUT Valet key programs good with both cars (now i can lock unlock START engine with the same VALET key haha)

so in my opnion system works good because I CAN program VALET key

any opinion how to program master key

or just try to change that theft module under the dash from junk yard with working master key and thats all?