I just installed a Flow Tech 3" cut-out over the weekend, it was placed as far back after the cat as i could get it...probably a little passed the passanger seat. I had it open for the first time today, drove it to work and back. On my way to work it was fine, on the way home the SES light came on. I pulled off into a parking lot, turned my car off and re-capped the cut-out. When i restarted it the light was off. I don't get it, it's nowhere near the O2 sensors or anything and i am still running through the cat even with the cut out. Could the difference in back-pressure actually cause the SES light to go on? I'd appreciate any suggestions or help, i don't want to be afraid of uncapping the thing every once in awhile.

 

Pull the code and see what the PCM is mad about.
It could be something simple.
I don,t see a cutout causing a problem but you need to see what code it is throwing.

 

Yeah it doesnt make sense that a cutout would throw a code, see what it is.

 

A cut out should not make the ses light come on, like the others said, try to pull the code to see what is making it come on.

 

Check the code- P0400 is an EGR valve DTC. You can sometimes get the code with less restrictive exhaust. I do sometimes with the cut-out open.

 

I've had my cut out open since installation about a month ago. No codes.

 

I throw a P0400 all the time with my Borla set wide open (no plates). It's not my EGR, vacuum lines or solenoid. Just a lack of backpressure triggers the code. I just reset it and go on my way.

Shouldn't happen; but, it does.

 

I will have to check what code it is for sure before driving myself nuts. If it is a PO400 getting thrown from lack of back-pressure will it hurt my car to run with the cut-out open all the time if i keep getting that same code? Any way to prevent it from going on?

 

Nope, it won't hurt your car. I drove with the code for a long time and even took it to the track. The only fix I know of for OBDI is to have the code programmed out of the computer.