Codes P0137 / P0139 / P1800

Does anyone know which O2 sensors I need to buy? Which brand of sensors should I buy?

Any videos on how to best accomplish this task? I know the sensors are in tough spots.

Thanks

 

Anyone?

So far, I believe that one O2 sensor behind the CAT needs to be changed but need to find the right PN.

Also, this whole issue started when I changed the PCV hose and a day or two later all of these codes came up. Any relation?

 

I would double check the pcv and hoses. Anything rubber on these cars is no longer pliable and can crack easily.

 

I finally fixed this. First off had a bad 02 (behind the cat) and a code made me go change the PCV. Not sure you can change the PCV as it comes installed on the rear valve cover. So when trying to replace the PCV, it wouldn't thread correctly and obviously started throwing more codes.
Replaced:

• Spark plugs (they were due)
• Throttle body cover (bc I was in there already)
• Rear valve cover (OEM from Nissan & has the PCV installed)
  • This cleared all codes but the AFT CAT O2 sensor
• Replaced O2 sensor
  • No more codes and passed smog