I've had this code a couple times on my MKIV Golf. When I swapped to a R32 3 spoke from the 4 spoke stock wheel I changed the weight (damper) that is behind the airbag as the one that came with the 3 spoke was different. Well, this one didn't have a good spot for grounding that black cable like the 4 spoke did. So I crimped on an eyelet and put it grounded it on top of the weight. Fast forward 2 years, get the code. Open it up, wire is still there but I decided to drop a little solder in the crimp connection I added for the ground. That cleared it for a couple weeks and it came back. I just moved the ground from on top of the weight to underneath it. That way it is directly touching the metal base of the steering wheel.
With all these ground moves, I've checked resistance and it's always less than 1 ohm from the yellow connector that plugs into the clockspring to actual ground. This is a very finnicky system. From what I've read, it's looking for 2.2 ohms or less on all it's airbags. Another interesting thing I've found is the airbag connector on the harness side has a small coil inside it between the two leads, I'm not sure why... The airbag itself has no resistance which would make sense to me. Anyway, I just successfully cleared my light with the movement of the ground and we'll see how long it stays. If it comes back, I'm going to be looking at the airbag controller under the dash. I've read about them getting cold solder joints on the motherboard inside the case that can wreak havoc with codes.