I had a similar problem on a Jaguar S-type (my car previous to the GV) and it turned out that a "squib" had fired on the front passenger seat-belt anchorage point. I surmized that at some previous time, fierce braking had 'blown' the squib that tightens up the seat-belts in a sudden deceleration such as a crash. I was told by a mechanic the squib can be fired by heavy braking.
You can measure the resistance of the sqib with a common digital multimeter and compare it with an un-fired one. The fired one was o/c. The tiny current from the multimeter did not fire the squib as I was measuring it! They seem to need quite a current from the 12volt battery to fire.
I hate to admit it, but I frigged it with a half-watt resistor the same value as measured on the other squib. It worked as the micro will simply check resistance and any shorts to ground. So make sure if you use the frig. of mine that the dead squib is completely disconnected.
From what you put, I've a funny feeling you might have multiple dead squibs. But I hope not.
I think the resistance on mine was something like a 1000 ohms, but a check with a live squib should ensure the correct resistance.
Hope this is the root problem, i.e. the pre-tensioner squibs, as it was fixable with a frig for me.
Leedsman.
Forgot to mention. If you find dead squibs, you might need to clear codes possibly by disconnection the battery negative for a few minutes after fixing. Cheers.

 

After messing with this for months and not having much luck, I had the oncoming pressure of the next annual inspection, so I decided to go deeper on this than before and check any airbag system components I could get access to without really taking things apart. I found a corroded pin on one of my front frame rail impact sensors:



I went ahead and replaced with a new one from eBay and cleaned that connector really well. Airbag light was still on Still same situation with airbag codes, as I've described in previous posts. The pin may have been corroded but intact, and came apart when I pulled the connector, hard to know.

I caved and took it to a shop that's trustworthy. The guy only charged a half hour of labor for the diagnostic and said his system told him the OCM wouldn't communicate and that there was a VIN mismatch. Couldn't go further there. I went home and pulled out the old OCM that I replaced with an eBay one, thinking maybe he could rescan with the original.



The plastic housing oddly shattered when I had removed it months ago, but I figured I'd see what happens when I plug it back in (plenty of electrical tape holding things together), since the replacement one apparently wasn't compatible. Reconnected battery, BOOM! Airbag light is off.

It's a little dissatisfying that I don't know exactly what fixed the problem, but I suspect it was that front impact sensor, it's just hard to know for sure because that replacement OCM was masking the effect of the fix, whatever I did (over months of tinkering). I don't suspect it was just reconnecting the original OCM alone, because I cleaned and wiggled the connector on that thing a lot before I ever tried replacing it. Anyway, just glad this year long saga is over and I didn't have to replace the main airbag computer or anything.

For reference, the original OCM part number was 4686943AI, and the replacement one I got was 4727388AD. I thought I did some compatibility check on that when I bought, and it was supposed to be compatible, but apparently not.

 

KInda what i tried to tell you the used ones wont work like that vin errors and such. as for the other errors messing around cold have moved wires and such