I got a custom 2.25 inch exhaust made and about 4 hours afterwards both lights came on. Can anyone tell me what the deal is?

 

go into the FAQ and read on how to reset your maintenance light. It's mileage related and was completely coincidence.

since you never listed you year I don't know if your Accord is OBD1 or OBD2. So I'll say this... if it's pre96 then go into the FAQ and see how to pull the CEL code(s). if it's 96+ go to AutoZone, or some other parts store, and get it scanned for free.

Then do some research on what the code(s) mean.

 

dont really know if its the same with the accords, but wen i had my ep with a testpipe, i had to mod one of the o2 sensors to remove the light.

 

Ok. Its a 98, and the folks at auto zone said my cat is flowing more than usual. Guessin my cat is past its prime.

 

i had the same problem and if there is not o2 sensor set in the the check engine light remains on and if you remove it using the scanner in a couple of minutes it will return..so im guessing its your o2 sensor next to the cat..

 

I dont think its the sensor. I upgraded to iridium plugs, performance wires/coil/cap and rotor, and the light went off. Maybe it was tune-up time.