Three hundred bucks for a new car key? Nonsense! When you lose your keys or want to have an extra made for that new teen driver, don’t let the stealership lighten your wallet. Just pull the ECU and hack some hex to add the new keys.
The video below is a whirlwind tour of the process [speedkar9] uses to reprogram Toyota ECUs to allow new keys to pass the security test on your new(er) car. Since the early 2000s or so, most manufacturers have included RFID chips in their keys so that only known keys will start a car. In Toyotas, this is done by an RFID reader in the steering column that passes the inserted key’s code to the engine control unit. If the 8-byte key code matches one of three values stored in the ECU, the car will start. Clearing the EEPROM in the ECU is the focus of [speedkar9]’s process, which connecting to the EEPROM and reading the contents. His rig includes an RS-232 serial connection, so the hardest part of this hack might be rounding up a PC with a DB-9 jack, but once you’ve got that covered, it’s just a little bit-bashing to “virginize” the ECU to ready it for reprogramming.
The details of the procedure will vary by manufacturer, of course, and cars of a more recent vintage will likely have even more security to worry about. Might you even run afoul of DRM like you would by hacking a tractor? Perhaps. But $300 is $300.
Thanks for [darkspr1te] for the heads up on this one.