I got an 03 04 and 07 07 code on my ecu today. It's for the knock sensor and the rear heated 02 sensor. My question is this, Should I just reset the computer or replace the sensors? I had a similar code pop up when I installed the CAI and I just reset the ecu. Now, about a month later the codes are back. Should I worry or just reset the ecu? The car seems to be running perfectly ok. Any input will be appreciated.

 

You should replace the 02 sensor.

 

both or just the rear one?

 

If it ain't broke, don't fix it.

 

707 refers to the rear O2 sensor located either on or after the main catalytic converter. It is used only for diagnostic purposes and does not affect the operation of the engine. However, if you want to replace it (recommended), the part costs around $100 from a Nissan dealer. Don't confuse this part for either of the two front O2 sensors, which must be replaced if they malfunction.

As for the knock sensor, it is pretty difficult to replace, so I would replace the rear O2 sensor and hope the code doesn't come back.