Just finished putting in a custom Y-Pipe. Sounds great! However, the Service Engine Soon (SES) light keeps turning on. At first I decided to resest the ECU (unplugged battery over night). That seemed to work. I drove 45 min to work and still great. After work I decided to puch it a little and it came back on. I have reset the ECU again and this time I am just going to cruise with the car for a day or two to see the results. I did notice that when I punch it, at high rpm I hear a whistling sound. Could this be an exhaust leak or is that how it's suppose to sound? Anyways, by cruising the car and if the SES light doesn't come on I'll punch it again and see if the SES goes on. This will help me determine if the whistling noise is an exhaust leak.

Anyone have any thaughts?

 

Custom Ypipe, Well my first thoughts are did you place the O2 sensors back in or just disconnect them completely?

Cause technically you shouldve had two coming off the stock and then need to put them on the custom pipe. This is my first suggestion.

Need to know what you did there before I start digging. Only other thing is if you did retain them, then the only thing left is one of the O2 sensors got messed up.

Dixit

 

Both O2 sensors were put back on. I am thinking that if one of the O2 sensers was damaged then reseting the ECU would not have an effect on the SES light. BTW, just came back from a 15-20 min cruise and the SES light came back on.

 

Most likely one of them has been damaged. You have to be very careful with these O2 sensors. I know it is a pain, but while putting it back on, you need to sort of wind it in reverse like three full turns before actualy putting in the hole because that way you eliminate the possibility of putting a tight strain on the wire and might have caused a short/loose wire.

Dixit