I've seen a few topics on the subject but yet to find a clear explanation. I did write this quickly and I'm sure it could use some edits but it's a starting point. I am happy to elaborate on any of the information listed, I just ask that you reference me if you're reposting the information anywhere!
VW immobilizers (Golf/Jetta/Passat)
immo2 - North American cars 2000-2001 (some vw/audi)
Keys are programmed to the dash only, do not write anything to the chip, can be reprogrammed on another immo2 car. Immo3 chips can be programmed to immo2 cars if unlocked. Programming can be done via vcds as long as you have the SKC.
immo3 - 2002-2005ish (depends on chassis)
Keys are programmed in the dash but dash and ecu are synched with 'component security' (CS), the same info that is written to the chip of the key. 6 bytes are often in the ecu (sometimes 7) but 7 are in the dash. No special coding is required to the chip before programming, it just must be virgin or locked to that particular car's CS (ie a key already used on that car). Programming can be done with vcds as long as you have the SKC.
immo4 (2005.5+, mk5/mk6)
Early immo4 cars, 2005.5 and 2006 may or may not require precoding the key before programming. I have done several 05.5 and 06's with new chips but they must be 'CAN' chips. Ordinary id48 glass chips can be converted to a VW CAN chip if you have the proper tools and lock to the car once programmed like an immo3 chip.
2007+ cars require precoding (exception is the city golf/jetta that still uses immo3) the chip before programming to the car. The CS bytes are written to the key (making it a 'dealer key')and it is locked if you order the key from the vw dealer so their equipment can add it to the dashboard. For these cars, you cannot simply go to a vw dealer with a virgin chip with cut blade and have them program your car. I have heard several different excuses why but the truth is that most do not fully understand the electronics behind the system (some do, many don't) and they have just been told that only dealer keys ordered from VW will work. There are some aftermarket solutions that can do this on mk5/mk6 cars but as of now, the dealer isn't capable. Once you have a precoded key/dealer key, it can be programmed into the dash to start the car.
Programming can apparently be done with VCDS if you have a 'dealer key' and the proper pin but I have only tried a few times and it didn't seem to work. I'm sure it can be done, I just use other tools that are more straightforward to get it done!
There are essentially two parts to the immobilizer chip, the fixed code that is written to the dashboard and the writable section that is written with CS when the chip is locked to the car. Both pieces must match before the key will be accepted by the car to allow it to start. This is why used keys/chips cannot be reused.
Very happy to answer any questions on this topic as I have dealt with many different systems and models. Will try to elaborate and add pictures in the future if desired.
VW immobilizers (Golf/Jetta/Passat)
immo2 - North American cars 2000-2001 (some vw/audi)
Keys are programmed to the dash only, do not write anything to the chip, can be reprogrammed on another immo2 car. Immo3 chips can be programmed to immo2 cars if unlocked. Programming can be done via vcds as long as you have the SKC.
immo3 - 2002-2005ish (depends on chassis)
Keys are programmed in the dash but dash and ecu are synched with 'component security' (CS), the same info that is written to the chip of the key. 6 bytes are often in the ecu (sometimes 7) but 7 are in the dash. No special coding is required to the chip before programming, it just must be virgin or locked to that particular car's CS (ie a key already used on that car). Programming can be done with vcds as long as you have the SKC.
immo4 (2005.5+, mk5/mk6)
Early immo4 cars, 2005.5 and 2006 may or may not require precoding the key before programming. I have done several 05.5 and 06's with new chips but they must be 'CAN' chips. Ordinary id48 glass chips can be converted to a VW CAN chip if you have the proper tools and lock to the car once programmed like an immo3 chip.
2007+ cars require precoding (exception is the city golf/jetta that still uses immo3) the chip before programming to the car. The CS bytes are written to the key (making it a 'dealer key')and it is locked if you order the key from the vw dealer so their equipment can add it to the dashboard. For these cars, you cannot simply go to a vw dealer with a virgin chip with cut blade and have them program your car. I have heard several different excuses why but the truth is that most do not fully understand the electronics behind the system (some do, many don't) and they have just been told that only dealer keys ordered from VW will work. There are some aftermarket solutions that can do this on mk5/mk6 cars but as of now, the dealer isn't capable. Once you have a precoded key/dealer key, it can be programmed into the dash to start the car.
Programming can apparently be done with VCDS if you have a 'dealer key' and the proper pin but I have only tried a few times and it didn't seem to work. I'm sure it can be done, I just use other tools that are more straightforward to get it done!
There are essentially two parts to the immobilizer chip, the fixed code that is written to the dashboard and the writable section that is written with CS when the chip is locked to the car. Both pieces must match before the key will be accepted by the car to allow it to start. This is why used keys/chips cannot be reused.
Very happy to answer any questions on this topic as I have dealt with many different systems and models. Will try to elaborate and add pictures in the future if desired.
