General Maintenance & Repairs - List of problems after leaving country

I was out of the country for 4 months and my 2000 SS was barely driven or even started. Shortly before I left, I bottomed out and one side of the y pipe was ripped off for a day, resulting in one (longtube) open header. When I left I had no lights on, and yesterday when I got in my car I had service engine soon, which ended up being oxygen sensor(the one that was running open header for a short while) no reading. I also have the abs inop, brake, and service required lights all on. I tested my abs and it is not working. How do I go about figuring out how to fix all of this? Could the fact that I was running that one open header have caused the bad oxygen sensor?

It could have ruined the oxygen sesnor, but I don't know about the other stuff.

TTT anyone?

Check your brake fluid level. Check for leaks. Is the service required light the oil change light or the Service Engine Soon light?

I need an oil change too, the "change oil", "service engine soon", "service required", "brake", and "abs inop" lights are all on. well the change oil turns off after a minute. I know why the SES light is on, but the other three I don't know what is wrong. I have full brake fluid, I'm going to go try to inspect what I can of the brakes now.

Check for blown lights in the back. What kind of lights you running for brake/signal bulbs?

Thanks for the help. I had already looked up and found out that could cause it but it was a 3rd ABS fuse not with the other two that I looked over. I also put a new o2 sensor in and everything seems to be fixed. Thanks for your help!