sbman - photo of the ECU internals below. This is the borrowed one, but I imagine they're identical from a hardware perspective, the only difference being how the chip is programmed? The chip he read was the one in position 'IC2' on the board, the one to the top left of the much larger chip at 'IC1'.
The numbers on it, should they not be clear, are:
93LC66
I/P SEW
9545
View attachment 2153740
IC1 is the main CPU chip (single chip computer) and it may be a specialty part made for/by the immobilizer company so no documents available on it of course, they keep it mysterious on purpose. IC2 is an EEPROM that is read/write memory storage, intended to be semi permanent and it is where the key codes are stored. IC3 looks to be the RF chip that handles energizing the coil and reading signals from it through the 'amplifier'. The item TR15 is probably related to that as well. The rest of the parts are various basic electrical parts for circuit protection and hardening against the automotive environment. The blue one X11? is a crystal oscillator, probably for the CPU's master clock.
If you search 93C66 key programmer on google, you'll get a lot of hits, such as this one, and many others.:
How to use Toyota 4D G chip key programmer
As for official Toyota support,
@cruiserdan is of course correct. The Toyota sanctioned fix for this is to buy a new immobilizer ECU with a key already paired up. Toyota never offered any support for reprogramming the 'master key' or reflashing the immobilzer ECU, only the aftermarket took up that cause. The issue isn't the technology can't do it, it's Toyota saying no. On the cars with this system built into the EFI computer, you have to replace the entire EFI computer.
The aftermarket didn't accept this and figured out how to read (and write) the little EEPROM chips in both the stand alone and integrated immobilizers. As each new system has come online, the aftermarket has created solutions to duplicate keys, fix/change/flash ECUs and generally get around it all.
As for getting a new key for your existing immobilizer, that is going to come down to the tools and skills that your locksmith has. I tend to doubt the ECU is bad. It's possible but seems unlikely to me, I think your key just went bad for whatever reason. I don't know that I'd want to have the locksmith that has failed to make a key multiple times have a go with the working ECU/Key system, since the EEPROM IS a read/write device, it is possible that if he doesn't know what he is doing and his tool is capable of writing that he could brick that system.
OK. So here's what I would do, if all this was in my hands.
- Ask this existing locksmith if he can duplicate the transponder key, from the working KEY.... NOT from the working ECU. Have him try that and if he succeeds, that's great! If he fails, find another locksmith until you find one that can do it. Now you have two working keys that both work with the one working ECU, with one of them physically cut for your lock cylinder.
- Next I'd buy an EEPROM programmer device for my computer. USB E-Eprom programmer - 24xx, 93xx, 25xx, 95xx eeproms for $20 although I might have one around here somewhere....
- For each of the next two steps, I would de-solder the EEPROM chips from their ECU circuit boards. This ensures that I don't damage the other circuits on the immobilizer and that I get clean reads/writes from the EEPROM chips. This requires a certain level of skill and tools to do so without damage.
- Now, I'd wire up the programmer to the working ECU's EEPROM and read the data out of it, getting a complete image of it's data and save that to my computer. Solder the EEPROM back into place. This gives me an image of the working ECU on my computer.
- Finally, I'd wire up the programmer to the 'dead' ECU's EEPROM and flash the image onto it that I saved in the previous step. Then read it to verify it. Solder it back in place.
By doing all that, I've effectively duplicated the 'working' immobilizer and both trucks use the same transponder code. I'd finish off with getting another duplicate transponder key made that is cut for my truck so I have a spare, because this whole scenario sucks and I wouldn't want to repeat it. I understand if that series of steps isn't something you'd want to do, but it's what the super expensive 'key programmers' are doing sort of automatically. I have a background in MCU programming and electronics assembly / testing and troubleshooting so I'd be comfortable doing it and if it didn't work, only the effort is lost.
EDIT: I think on newer vehicles the immobilizer can be reset through the OBD2 port with special dealer tools not sure though.