Q: Catalytic converter turning bright red

You have two valve cover gaskets, one for each bank of cylinders. They should both be replaced at the same time. The left bank(front) is much easier and there are less parts to remove. The right bank(rear) is more involved and has more possibilities for error. The catalytic converter will glow red when too much fuel is reaching it. It’s purpose is to burn the excess fuel and air from normal combustion through a chemical process. When there is a misfire, much more fuel and air reach it and it burns too hot. If your engine is running rough, this indicates a misfire. During your repair, if an ignition coil was not plugged in, this could result. The 5 codes set will point to what was not done properly when the gaskets were changed. Do not run the engine until it is repaired. The converter has the ability to melt itself and they are very expensive to replace. I recommend having a certified mechanic diagnose your vehicle and replace your catalytic converter if necessary.