I have a 2003 Yukon 5.3 and recently installed long tube headers and off road ypipe.

Tried a set of 2001 O2 Simms and still getting the SES light due to the O2's, light came on with simms and without.

Guy that sold me the simms is very cool and I'm sending them back to him, but wanted to check and see if the SES light is causing me any reduced horsepower, like does it send the computer into limp mode or anything?

Truck doesn't feel weird, but the crazy volume of the cutout and headers may be causing me to have a sense of SOTP power that is slightly distorted.

Also, any guesses as to what I should be putting down rwhp wise? 2wd, 3.73's, intake, headers, no cats, HPP3 93 octane tune, and cutout?

 

Any idea what SES code you're actually getting?

Certain DTC's will cause the ETC to actually limit throttle position, response, etc. So tracking down what the code is would be critical to figuring where to start looking.

 

My guess is, that your truck is doing it because your gay! Just a hunch though.

Will

 

Hey Jhelms, is SMOC's site down? I can't seem get in.

Will

 

We pulled and cleared the codes, and the light came right back on again. I can't remember the actual letters of the code, but it was the back o2 sensor readings.

Happened with the 2001 o2simms plugged in and with no simms plugged in

 

You can have your PCM tune modified to turn off the codes for the rear O2 sensors. That way the SES light will not come on. If the light is for the rear O2s it will not affect the performance of your truck.

 

I'll tell you what's gay, the fact that apparently SMOC is down, that sucks!!!


I know, just didn't want to fork out the money for a PCM tune right now, especially if this particular code isn't triggering lost hp. I have the HPP3 just for generic trans tuning, 93 octane, etc. Will upgrade the tune when I get the cam and a couple of other bolt ons.

Very cool, thanks for the info, it's a relief to know it's not pulling any power due to that particular code.

Thanks for the input ya'll... BTW this thing is LOUD with the cutout open, headers and no cats I love it!!!