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Help Code P0420 Bank 1 Oxygen Sensor Fail

sschwaeble93

sschwaeble93

New member
Hi,

I need help. I have a 2006 Pontiac Grand Prix Gxp and I'm getting a check engine light coming on code P0420 and the service engine

soon light also pops up on the DIC while I'm driving. I had the car scanned and wanted to know where bank 1 is for the O2 sensor? Thanks

for your help in advance. Already put a new cat converter in over the weekend but still getting the code.
 


No it is a own fit car. What is the best way to remove the o2 sensor on the exhaust manifold pipe?? Really tight there against the firewall. Thanks.
 
And..the code isn't for a bad sensor.

Bad sensor codes include ones for sensor slow to respond, bad voltage, heater etc.

P0420 is the code that says the rear sensor isn't seeing the catalytic doing a good job of reducing the emissions .
 
Thank you for your help. I will probably just replace both. What is the easiest way to get the upstream O2 sensor removed. I had trouble trying to get it loose from the top. Is it easier to get to it with the car jacked up from underneath. Thank you again.
 


you need a o2 socket for the upper one. i got mine out from the top with bout a foots worth of extensions. that got my ratchet right under the cowl and the pipe on the ratchet cleared the engine.


one of these, got mine at HF for like 7 bucks.

image_23171.jpg
 
I have one of these, same basic thing.
image_13142.jpg

It's 1/2" drive..so a couple extensions and a nice long 1/2" ratchet. I've had one that fought to the point I had the car running while I fought it out.
 
mine was just damn tight, once it broke free it came right out, the new one should come with some anti seize for the threads.
 
in another thread 91parkave i think it is, said its in the same place on a v8. exhaust is pretty much the same. same with the banks and locations. 1 and 2
 


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