OBDII code P0420

A few months ago I was in the Edwards/Mojave area getting dirty. I hit a nice puddle of mud and right after I got a MIL. I did not notice any performance difference, so I kept on trucking. I purchased a OBDII tester after moving to the East Bay. After reading the code, it came up as P0420, I cleared the code and within minutes of driving the code would come back. so I got under the beast and inspected the exhaust system and I didn't find any obvious leaks. but thinking back I did break the systems when I dropped the Trans to replace the RMS. I found that the two of the three bolts that tie the 2 Cats together, on the passenger side, was not torqued correctly. so I replaced the hardware and seal. I buttoned up the system and took it out for a spin but did not clear the code. The code did not go out. so got in check the system via the tester and then cleared the code and when for another spin. The code has not come back and after several tests I am code free. total price to fix this was problem was $130.57
OBDII reader, hardware, liquid Wrench, and a seal.
Lesson learned: Always check the torque and NEVER reuse exhaust seals.
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01 Khaki Frontier XE V6 CC
EAST BAY