Catalytic Converter and O2 Sensors p0420, 1166, 1167

[Tasteful]

Hey Everyone!

I am brand new to the site and I'm looking for help! New owner of a black 2002 ep3!

A few months ago, I threw code P0420, catalyst efficiency below threshold, which would come on if I cruised at 55mph. If I was above or below that range, it would stay off indefinitely. Recently, I threw 2 more codes: p1166,1167 which deal with o2 sensors and airflow.

I think it was my mistake but is it possible that my catalytic converter went bad, and that eventually threw my o2 sensor? Before I replace both the converter and o2 sensor (upstream, downstream?) I wanted to ask for an opinion! Please help!!

[Tnhatch03]

how many miles on the EP?
is it the original o2 sensor?

i would probably check the sensors before purchasing a CAT. i had an issue once and it ended up being the primary o2 sensor.

[tht1guy]

I have a cat if you need one

Sent from my HTC Thunderbolt...

[talonXracer]

Welcome to EPhatch

Now does your car have a stock exhaust? It does sound as if the front o2 sensor, also called the A/F sensor, probably needs replacing. But best to take a peak under the car and see if it has a stock exhaust first before assuming anything.

[Tasteful]

It is NOT the stock exhaust and the engine has 150k miles. I have found some bosch PRE-CAT o2 sensors for around 60 shipped; is the pre-cat the primary sensor? I also wonder because, before i got errors p1166, p1167, I got codes p0420, catalyst efficiency below threshold. I am thinking about going out and buying that pre-cat sensor and seeing what happens...

and so far, thank you all for responses!

[Euro-Yellow-Ep3]

i def sounds like the primary sensor, keep us informed

[talonXracer]

It is NOT the stock exhaust and the engine has 150k miles. I have found some bosch PRE-CAT o2 sensors for around 60 shipped; is the pre-cat the primary sensor? I also wonder because, before i got errors p1166, p1167, I got codes p0420, catalyst efficiency below threshold. I am thinking about going out and buying that pre-cat sensor and seeing what happens...

and so far, thank you all for responses!

If it is not the stock exhaust the cat is probably not even there, that would explain the P0420.

If you found a o2 sensor for 60$ than it is almost certainly the wrong type or used and of questionable condition, The Kseries requires a WIDEBAND 4 wire preheated o2 sensor, very expensive. Steer clear of Ebay or you will probably end up with the wrong sensor trying to save cash.

[Tnhatch03]

i bought an odyssey K24 o2 sensor... wayyyy cheaper... i do not recall the specifics though. you would def. want to search before hand.

[talonXracer]

Are you sure it was an odessey, i wasnt aware they came with a Kseries, I only seen 6 bangers, sure it wasnt the Element?

[Tasteful]

Your right. I looked at that part and the correct one, Bosch part 13680, upstream 4 band sensor, is around 130. Before I purchase it, however, I will inspect under my car to see if I have a cat.. :)

Here is a picture of the new ride. No name yet.

<a href="http://s163.photobucket.com/albums/t286/Davidtheromanian/?action=view&amp;current=small.jpg" target="_blank"><img src="http://i163.photobucket.com/albums/t286/Davidtheromanian/small.jpg" border="0" alt="Photobucket"></a>

[Tnhatch03]

Are you sure it was an odessey, i wasnt aware they came with a Kseries, I only seen 6 bangers, sure it wasnt the Element?

it probably was the element...

i guess i was have right. lol

[ace of spades]

Hey Everyone!

I am brand new to the site and I'm looking for help! New owner of a black 2002 ep3!

A few months ago, I threw code P0420, catalyst efficiency below threshold, which would come on if I cruised at 55mph. If I was above or below that range, it would stay off indefinitely. Recently, I threw 2 more codes: p1166,1167 which deal with o2 sensors and airflow.

I think it was my mistake but is it possible that my catalytic converter went bad, and that eventually threw my o2 sensor? Before I replace both the converter and o2 sensor (upstream, downstream?) I wanted to ask for an opinion! Please help!!

I'm in the same boat. I have been living with my cel p0420 for a few months now. I was told by other EPers that I should replace my cat but I'm going to try a primary o2 swap first.

If it is not the stock exhaust the cat is probably not even there, that would explain the P0420.

If you found a o2 sensor for 60$ than it is almost certainly the wrong type or used and of questionable condition, The Kseries requires a WIDEBAND 4 wire preheated o2 sensor, very expensive. Steer clear of Ebay or you will probably end up with the wrong sensor trying to save cash.

I recently bought a secondary o2 from ebay after I did a lot of research first. I had to locate compatible aftermarket sensor part numbers, then searched those numbers on ebay. worked out well for me. I was going to do the same when I look for the primary.

[talonXracer]

Just so you guys know, the primary has no input into the P0420 CEL. That is entirely generated by the SECONDARY sensor, unless the primary is so far out of calibration and running uber lean that the cat is being burned up. But there would be serious drivability issues at this point.

[ace of spades]

Just so you guys know, the primary has no input into the P0420 CEL. That is entirely generated by the SECONDARY sensor, unless the primary is so far out of calibration and running uber lean that the cat is being burned up. But there would be serious drivability issues at this point.

I had my numbers mixed up. I had a p0420 for months and the secondary o2 swap fixed it. my recent (and current) cel is from a cat inefficiency or something. I forget the code. I was told to replace the cat, but it's pricey so I'm hoping the primary replacement works. car still drives and feels the same.

[talonXracer]

swapping out the primary would do absolutely nothing for your issue other than to lighten your wallet.

Any CEL that is cat related is either the cat or the secondary sensor if there is no error codes for the primary at the same time.

These CEL's are generated when the temp of the exhaust gases are not lower at the secondary location when the ECU compares the temp between the primary and secondary sensors.


Your cat is covered by a 8 year 80K mile warranty, if you are below those points you can get a new one for free.