2001 gmc sierra 1500 dual exhaust

I have had dual exhaust installed a couple of months ago and now I am getting error codes and my service engine soon light is coming on. No sensors were unplugged when exhaust was added. I believe it is O2 sensors with lean readings on bank 2. Can I do something to fix the problem or do I need to go back to the original exhaust?

I think there is an O2 sensor behind the converter(s) on all models, and should still be there after an exhaust replacement.

What kind of exhaust did you have installed? Larger tubes mean less O2 at that point and will require recalibrating the exhaust sensors (meaning adding all new O2 sensors).

Most aftermarket dual exhausts have provisions for the sensor and don't require this.

TR