Used Key FOB and locks replacement

[Brandonld9181985]

Looking at buying some used locks and Key fobs cut for them, my question is do I need to have them programmed with the ECU if I buy them? It’s a better deal than paying dealership almost 300 for a fob to be cut and programmed! Thoughts? Or anything else I would need to do in order to get the trunk and door locks to work once I get them?

 

[Brandonld9181985]

Looking at buying some used locks and Key fobs cut for them, my question is do I need to have them programmed with the ECU if I buy them? It’s a better deal than paying dealership almost 300 for a fob to be cut and programmed! Thoughts? Or anything else I would need to do in order to get the trunk and door locks to work once I get them?
It’s for my 2002 Jetta TDI

 

[Mass. Wine Guy]

Depends on which generation VW you have. My MK3 key can be duplicated by non-dealer vendors. MK7 keys are dealer only, as far as I know.

 

[Brandonld9181985]

I forgot that in the Original Post, it’s a MK4 jetta TDI

 

[Vince Waldon]

It's a fairly sophisticated anti-theft system with two distinct parts:

- an RFID tag embedded in the key that allows the car to start
- a battery-powered radio transmitter (the fob) that locks and unlocks the doors etc

The keys, the specific cluster, and the specific ECU all have to be aware of each other and this training process takes multiple steps and *two* different pieces of software, one of which in particular is pretty expensive (unless you're willing to roll the dice on a virus-ridden clone). That said, there are places that will rent this software.

Many existing threads on this topic here so lots of reading available; in many cases folks decide the dealer is not a horrible option given what their time and effort is worth. Your call, of course... all depends on how hands-on you are comfortable getting.

Mazda charges $600 for a Odyssey key (don't ask) so it could be worse.

 

[pkhoury]

Looking at buying some used locks and Key fobs cut for them, my question is do I need to have them programmed with the ECU if I buy them? It’s a better deal than paying dealership almost 300 for a fob to be cut and programmed! Thoughts? Or anything else I would need to do in order to get the trunk and door locks to work once I get them?

Assuming this is for your 2002, you could delete the immobilizer deleted and it would work as-is, albeit with the immobilizer light on the instrument cluster flashing.

I did this on one or several of my cars. You'd obviously need a lock cylinder for the rear hatch/trunk (not sure what car you have), driver door, and ignition. I also think there was a change in fitment and cable between immo2 and immo3 (your car, 2002, would be immo3).

I also think I've read that immo3 keys can't be re-paired to another immo3 system, but immo2/3 keys can be re-paired to an immo2 system. So to get it to pair, you'd need to replace the RFID chip inside they keys (valet and fob).