Just trying to understand the photo. Is the black part what's left over from the broken off plastic of the sensor? If so, you can cut or break that part off to get to the bolt in the center and see if you can get some vice grips on the bolt to turn it out. If it won't budge, I'd grind it off and see if you can get a drill in there and drill it out (might have to remove whatever's in the way to get a drill in there?). Is that fixed nut accessible from the wheel well? If so, you break or grind it off and replace it.

Alternatively, what about relocating it very, very close to the original one? In order for the sensor to work correctly, does it have to be in that EXACT location, or can it be an inch off? You can drill a hole for the new bolt to go through, then reach through that access hole with a nut and washer (or just a nut) for the bolt to fasten into.

Warning about Ebay: You could get fake/knockoff TRW parts. I'd try RockAuto because they also have closeouts on some TRW parts (recently got some new TRW suspension parts at a deep discount).

 

I think the black or dark blue part could be plastic remnants from the sensor. I'll know for sure when I revisit this later this week. The sensor from the local dealer is $117. I found a used one on Ebay for $40. It has the same part number and looks identical. I checked Rockauto but haven't found it.

 

The welded nut broke free. Need to use pliers to grab the nut through the openings to get bolt out. If there’s not tension on the nut, it will keep spinning in place.

 

The only access I can see, I put a red arrow. You will need a pair of curved needle nose pliers or the smallest pair of locking pliers.

 

Interesting, because my 2004 has a slightly different setup. It's a Toyota/Denso sensor and isn't bolted onto the body the same way as yours is. The Denso sensor has an integrated bracket and the sensor is bolted to the body with two bolts above and below the sensor. You can see the top bolt in the 1st photo below. The access hole isn't as large as in your 2005 either. If your set up is similar to mine, you might be able to access it by removing the battery and the air intake tube, but the access hole you have looks......well......accessible. I'm pointing to what might be access in the 2nd photo below. The battery is removed in this photo.

 

The spinning part was the aluminium sleeve from the sensor. The holding nut on the other side of the hole didn't rotate so that was good news. Had to cut the sleeve using a dremel to expose the bolt inside, which came off easily with a pair of pliers. I had to remove the battery, the plastic battery tray, as well as the metal battery bracket to get both arms down there to feel the bolt and nut on the other side of the pre-drilled hole. That also gave me more room to work with the dremel. I'll get the replacement bolt from the dealer tomorrow. The sensor arrived today but I won't know if that'll fix the airbag light until tomorrow.

 

Update: the $40 sensor from Ebay works. The airbag light is gone. It feels good to not have any warning light on the dashboard.

I had started to replace the nuts and bolts on my exhaust manifold to fix an exhaust manifold leak but it got dark, and I needed my work car tomorrow, so I put everything back together. Started the car, airbag light is gone. I pulled on to the street for a test drive but the check light came on. I stopped the car, turned off the engine, went over in my head to see if I missed anything. Crap, I forgot to reconnect the oxygen sensor. Popped the hood and reconnected the o2 sensor. Turn the engine and the check light is still there. Went back home, turned on BlueDriver and cleared all the codes and rescanned it. Check light disappears. It better stay gone or I'll be majorly pissed. LOL

 

Check light disappears. It better stay gone or I'll be majorly pissed. LOL

Let us know how it goes.

 

Great work.