My CEL came on last night, car is running perfectly fine, tranny is fine, everything is fine. I put exhaust ( y pipe, and b pipe) on over the summer and recetly it sounds like it getting louder, i think it might have something to do with an O2 sensor in the exhaust? its an 02 with 40k on it, 6spd

 

If you don't have an OBD-II reader, go to AutoZone and have them check the code that is causing your SES light to come one. They do it for free.

You can always come back here after you get the code(s).

Peace.

 

1) Check for a loose gas cap. Remove it and reinstall it carefully, 3 clicks, make sure it's not cross-threaded and that the plastic retainer isn't caught under the seal, etc. If this was the problem, the CEL will go off after an hour of driving. (or less.) The gas cap has to make an airtight seal in order for the evaporative emission controls to work correctly, and it is a little too easy to wrap that plastic gizmo under the sealing surface so that it leaks.

2) If that doesn't fix it then there might be a real problem. If you know how to start up the diagnostic mode of the ECU then you can read the code yourself. Learn more:
http://forums.maxima.org/showthread....7&page=4&pp=30

Or patronize the service facility of your choice. Even though your car is out of the regular warranty period, there is an extended Federal emissions warranty that ought to cover a problem like this. But Nissan will not honor the warranty if your exhaust system has been modified.