Class C 1994 with e350 chassis exhaust manifold glowing red

Made a little progress, EGR reconnected, now manifolds are ok but exhaust pipe just after is glowing red. I checked to see if the muffler was blocked and i dont think so. I'm replacing the o2 sensor just on principle, it's rusty and I'm keeping this class C for a while :)

Anyone know how to do the reset on the computer that make it have to relearn usage and adjust gas consumption?