Flowmaster, now SES light is on

[airhead]

I just got a 40 series flowmaster installed on my 2000 silverado with a 4.8 it has a turn down before the axle. About a day after it was install the Service engine soon light came on, so i put it on the computer and it said emissions sensor, so i reset it, now it did it again. I unhooked the Neg. Batterey cable for an hour and the light came back on. Anyone else have this problem? Any way to fix it?

[AZdragger]

maybe the sensor got burned out???

[Z71Silverado98]

all the sensors should be just after the cats, they should have cut the muffler off but left the int. pipes, welding your 40 to those, check to see that they did this and make sure all the sensors are plugged in.

[00silverado5.3]

When i had my exhaust installed the shop burned the 02 sensor probably from the welding , and the light came on. We took it to the chevy house and they knew what had happend. But it was still under warranty so they fixed it for free.