I've got a C30 2012 model, and tried to programming a blank remote key, and I'm sure my original key and purchased ones are both semi-smart.
Here's the keys I've purchased: VOLVO RFK 434 31300254:

In a Volvo dealer, a 8-digi key id and 24-digi key code are required, which can be found after reading the barcode in the key case label. But the system just failed to program the key. The dealer told me that chances are that the keys are not for C30, and the correct part number for my car is 31300258, and they found nothing under 31300254.
But I'm confused:
What are the keys I've purchased(31300254), if the dealer finds nothing about it, does anyone know what is 31300254 and the compatible models for it?
As far as I can tell, only C30 and S40 used this key model and they are compatible each other, if the key looks the same and is semi-smart as what original one is, the key can be successfully programmed.
So any knows the possible reason that the programming failed?

 

That part number is not listed in a Volvo parts catalog. So I imagine the reason it won't program is because it's the wrong part for your car.

 

Thanks hoonk. It's just kinda weird that this item is not even in the catalog while it's a genuine Volvo product. I totally have no idea what models are these keys for.

 

Korea and Japan use different parts numbers/frequencies - but not that part number

 

So I guess that should be non-public part or test item or something alike. I've shared info with a local locksmith, and we'll see what he will find out from this key.

 

UPDATE:
1. I kind of figured it out, and part no. 31300254 seems not a part no. for separately ordered items, it should be the part number of the original pair of keys come with the new car.
2. The reason that it can't be programmed is that the ID48 is locked(not blank as the seller claimed), and I found a locksmith, he wrote a blank ID48 chip with the same chip id to replace the locked one in my remote. Then the remotes were programmed seamlessly.