p0420 code, which o2 sensor do i replace?

[Golman76]

i have a p0240 code and i have concluded that i need to replace an o2 sensor. It says bank 1, but does not state sensor 1 or sensor 2. if it is the one on the cat, will the spark plug non fouler go-around fix my problem?

say the o2 sensor is blown or clogged, will the non fouler fix still fix it? or do i still need to replace the sensor?

 

[otakurx]

code P0420 means that the PCM does not see the proper change in exhaust gas after the primary CAT, this could be a clogged CAT or your secondary O2 (the one after the primary CAT) is bad.

 

[copgtp]

spark plug non fouler go-around fix my problem

I might live under a rock, but can you explain this for me?

 

[GTPcoupe]

Does it say "PO420 catalyst system efficiency below thresh hold (bank 1)"? If so, I would say the rear 02 sensor.

 

[GTPcoupe]

I might live under a rock, but can you explain this for me?

This is useful if you have a hi flow cat that sets off the engine light and dont have a custom tune that deletes the code. It's just a peice you screw on to the end of the 02 sensor and then screw it in the pipe. It pulls the sensor back out farther so it detects less and tricks the sensor.

 

[Golman76]

yes gtpcoupe that is what it says. So if i use the non foulers will that make it good as new?

 

[GTPcoupe]

yes gtpcoupe that is what it says. So if i use the non foulers will that make it good as new?

It would probably stop the code from coming up, but you should see if it's the sensor or if you do have a clogged cat.

 

[Golman76]

how do i see if it is the sensor?

 

[OH4CompG]

Your rear o2 sensor almost never goes bad. Replace your cat

 

[97gtsc]

Just delete both problem solved