Check engine light is on after switching exhaust

I have a 93 GS integra, I put the exhaust on today (DcSports ceramic headers, cat-co High flow cat, and a Thermal Cat-back system). I Put the sensor back into the collecter pipe, and plugged it into the wiring harness. After about 15 of driving the check engine light came on? If you turn the car off for about 3 minutes, then drive it again, about 5 min’s later it will come on. Any suggestions on what this problem might be?
Thanks,
Matt

first find out what check engine light code its throwing.

Jump the service wire and pull the code.

I’ll try it tommorow.