Thread: SES Light

I have a 2001 Sentra SE. I installed a hotshot header. It threw 2 codes afterwards: P0420 and P0325. I ordered a spacer on ebay and installed it today on the 2nd 02 sensor. It is still throwing both codes. I didn't change the knock sensor (P0325) yet. Is it possible that the knock-sensor code affects the Cat code or vise-versa?

Just try clearing the codes and see if that corrects it.

When i installed the spacer i had my battery disconnected for awhile cause i did my oil change too. I thought that cleared the codes. As soon as I started the car, check engine light came on.

That doesn't always work. Go to a parts store and use one of their scanners to check your codes and clear them. Then see if they pop up again after that. If they do, go from there.

I redlined in 3rd gear 2 days ago and check engine light disappeared.

You probably had the two cats.

There are a few ways to get rid of the Rear O2 sensor code. You can put an inline resistor, or you can weld a bung behind the second cat and then extend the cable.

http://www.sr20-forum.com/general-maintenance/5791-how-most-obd-ii-remove-rear-o2-sensor.html