I have a 2004 Toyota Sequoia Limited that has the independent immobilizer unit behind the dash cluster. I am a technician myself but I usually dont deal with systems like this as I work with Heavy Duty and typically chevy 350 engines. Basically I know there is like 3 different types of vehicles 1 of which is a foreign vehicle which mine is and they say you need to pull the immobilizer, unsoder the cpu for it, flash the BIOS with the new key information so that the immobilizer can recognize the key. Now the dealership has said that the process is a little different that it gets programmed through the OBD2 port, as a technician I have the tools but not the knowledge to do it. Can anyone shed some insight as to how to get the immobilizer ecu reset so that I can get a key registered to the unit? I have an obd2 cable with laptop access but again toyota other than basic engine repair isnt usually my specialty.
Vehicle immobilizers come in various configurations; non chipped ignition keys with a separate remote for dual purpose use of locking/enabling factory theft deterrent and unlocking/disabling theft deterrent, chipped keys without a remote, and remotes broadcasting 24/7 for keyless entry/unlocking without pressing a remote button and locking without pressing a remote button with button presses always optional. According to online info, your Toyota should allow you, the owner, to program new chipped and cut keys, yourself. This is just one video; https://www.youtube.com/watch?app=desktop&v=HpsHhNOaDe. If I'm mistaken and this video does not help you in programming a replacement key(s), reply and I will delete this from disseminating misinformation. Basically, you should be able to buy replacement uncut chipped keys wherever its sold, bring it to key cutter with your original key, have it cut, then follow procedures for diy programming of the new chipped key to have the electronics learn a new chipped code in addition to your key. Some manufacturers allow between four to six keys for spares. Beware of dealers spouting disinformation about older immobilizer systems that have to be programmed by a dealer for new keys..... There's a world of electronics related to vehicle immobilizers and I haven't begun to describe them.
I am a locksmith and regularly make keys for Sequoia's.
Your immobilizer ecu is indeed behind the instrument cluster. Its a black box about 2inch x 2inch with a white label on it.
There is NO obd2 access to the immobilizer. You must either have a current working MASTER key or the immo box must be removed and the memory read directly from the eeprom chip. Once the memory is read you can manipulate it to add new master keys or extract current master key data or even return it to a virgin state.
This video I made is for a Avalon ECU but programming keys for the immobilizer box on sequoia is the same process. The only difference is that it uses a DIP8 eeprom instead of a soic8 eeprom and a different transponder chip.
Virgin file install : (will require a second procedure after on the sequioa's) https://www.youtube.com/watch?v=y1aG67hqvXg
Extract current key data: https://www.youtube.com/watch?v=Z2sJtWd63s0