2008 Kia Rio collison responsible?

I had a front end collison on this car. Was going about 40mph and the front passengers side was smashed up. Having nothing but problems since it's been back from body shop. My question is; if my engine light keeps going on and code P0300 comes up can the collison have anything to do with it? I'm told that kia has a "repair tsb" for this code because it's a problem with their cars so it cannot be accident related. I'm told that the short in the fuse block is not accident related because there was no damage done to it. There was over $9,000 in repairs done to this car. I would think a jolt like a front end collison could cause any problem, but I'm told that it has nothing to do with the accident and the dealership is backing them up. There was some kind of wiring done after the accident according to the body shop receipt. What wiring could this be? It states "Wiring Repair" and "Wiring R&I for pulls". What's your take in all of this because I'm having major dispute with this and many other problems.