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Oxygen Sensor

3K views 15 replies 4 participants last post by  jnbgoch 
#1 ·
Will the oxygen sensor throw the same P0420 code as the c/c??

Just had the c/c replaced and still getting the code. Any other suggestions are welcome.

Thanks,
Brad
:think: :think:
 
#7 ·
Hi jnbgoch

What that particular code (P0420) is saying, is the Cat isn't converting the engine exhaust properly and the rear O2 sensor (Bank-1 Sensor-3 (after the Cat)) is showing the same reading as (Bank-1 sensor-2 (before the Cat)) or close to it. Either way, the Cat is out of the required threshold for converting the engine exhaust. Hope this helps.:)
 
#10 ·
Hi jnbgoch

If the problem started right after the Cat change then yes, have them re do it. The OEM Cats are a "3-way" Design. Some of the after market cats are only a 1-way design and aren't up to the required Specs that the OEM ones are. Hope this clears things up and sorry for the delay.:)
 
#11 ·
A little update...

I took my van back in and they changed out the downstream O2...... Code came back. change out the upstream one next????

:screaming: :screaming: :screaming: :screaming: :screaming: :screaming: :screaming:
:banghead: :banghead: :banghead: :banghead: :banghead: :banghead: :banghead:

Brad
 
#12 ·
It's not an upstream or downstream O2 problem. It's Cat problem not converting the exhaust gases properly, that's what that code is saying to you. get them to "re-do" the Cat (if this problem started right after they changed the Cat), it isn't up to Spec. as mentioned earlier. Hope this helps.:)
 
#13 ·
Sorry, forgot to mention that. The p0420 code was my whole reason for having the cat changed. I changed the other two sensors myself and will clear the codes tomorrow and see where it stands. So now I have a new cat and all three new O2 sensors.

Thanks for all the info and suggestions!

Brad :ty:
 
#14 ·
Cleared the codes this morning and they are back. I called the shop and inquired about the cat, 1 stage or 3 stage. They confirmed 3 stage but are going to install a new one at no charge.

Should this not fix it, I will be finding a high cliff for Astro diving!

Brad
:crying:
 
#16 ·
Had the shop replace the cat (at their cost!). Got my van back and have about a hundred miles since picking it up. No codes...guess I can get my registration now!

fyi: code used to come on before I would get 30 miles down the road...

Maybe a bad one or they put it on backward (don't know if this matters)...don't know.

:layrubber: :layrubber:

Brad
 
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