I recently added Kooks long tube headers, & Y pipe w/high flow cats to my car. It's not a daily driver so today was nice and I took it out for awhile. Previous drives after the install didn't trip any SES codes but for some reason today it did. It still runs great so I'm positive it is the rear O2 sensors tripping the light like several others here have done. I intend to tune the rear sensors out but I wanted to wait until after I add my 3.73 gears and recalibrate the speedo at the same time. I installed some O2 sims but the SES light is still lit. I disconnected the battery hoping it would reset the ECM but no such luck. It's no big deal but the light is annoying. Am I missing something in getting the light to go out after installing the O2 sims???

 

You have to scan it. Otherwise you are just guessing.

 

I don't have a scanner tool and will get it to the local shop or Autozone for a scan. Is cycling the battery the correct procedure for resetting the ECM? I did notice a couple of small exhaust leaks the band clamps on the header collector to Y pipe and cat connections that need fixed too. Could that cause it to set a code?

 

An OBD-II code scanner costs less than $50. Its something you need if you are going to drive cars from 96 or newer.

Removing the power from the PCM clears most of the OBD-II codes. Best way to do it is to pull the "PCM BAT" fuse for 30 seconds. But if the problem is still there, the code is just going to come back as soon as the car is driven under the specific conditions that allow the PCM to run the diagnostic routine.

Exhaust leaks aren't likely to set codes. If they are before the pre-cat O2 sensors, they can cause other problems, like running rich, and that might set a code.