i just did a minor tune up on my z... its a 03 enthusiats 6mt with 70k miles.

i took the car for a spin after doing the following and now im getting a "Service Engine Soon" light.

1. installed a 2006 g35 manual tranny, tranny was completely dry so i put in manual tranny oil.
2. installed cat-less test pipes (holy **** now it sounds loud)
3. Installed a grounding wire kit
4. replaced the ac belt
5. new 8000k hid bulbs

i tried reseting the ecu, by unpluggin the ground for the night but the light came back...

Im posting here first to see if anyone has any suggestions before i take it to a nissan dealer.

WHAT COULD IT BE?

 

I'm guessing its an O2 sensor since you took out the cats, those are going to throw a error. Did you get O2 sims?

 

the test pipes have the o2 sensor plug...

 

Get the code read (autozone is your friend) and that will narrow it down.

 

thanks