Another P0420 thread

[rob_ess]

Ok so I am familiar with the O2 sensor code. Have had them on every car I've ever owned. 

The code is intermittant. After the start cycle the code is cleared and will be cleared for a couple of weeks. I have had one cat go bad but in a pre OBD2 car. But the smelled bad and had a huge power and efficiency loss.

Should i replace the O2 sensor and see if thats the issue? 

How many O2 sensors are on the 2014 2.4L? Not California or New York emissions? I found 1 right on the Cat it looks like. But thats it. 

[mechanical-idiot]

https://www.moparpartsgiant.com/

 

Check out this site.  It should have a diagram of the sensors for the 2.4 L.  If not, call them.  The number is on the top right of the home page.   They also have an online chat.

 

Goot luck.  Let us know how you get along.

 

mechanical-idiot

[rob_ess]

thanks. There doesn't appear to be a diagram showing the sensors so i will call tomorrow. 

[bfurth]

There should be two sensors (upstream and downstream).  Replace both, but keep in mind, this is only diagnostic work at this point.  Your catalytic converter may have failed as a result of the extraordinarily long spark plug change interval.  Start with the sensors, but be prepared for a new converter.

[jkeaton]

I'd have to agree that with the long spark plug change interval it could be the converter. I'd go ahead and replace all sensors at this point. 

Edited April 26, 2018 by jkeaton

[bfurth]

For clarity sake - I meant one upstream and one downstream O2 sensor, not two of each.  The upstream sensor is at the front of the catalytic converter just behind the joint between it and the exhaust manifold.  The downstream is in in the middle of the converter. They are listed as two different parts (from what I can see, though I don't have part numbers for either).

[rob_ess]

ok so there are two. are they both the same or is one a 2 wire and other a 4?

i figured if it was the cat, the code would be steady. my "check engine" light is off again. it will pop on once in a while and then go back off after however many start. That has always happened with 02 sensors for me.

i tried to get a temp reading from the manifold side and the after the cat but i can't get a consistent reading before the cat. Maybe too much residual heat? I'll start with the sensors. 

Thanks, everyone.

[jkeaton]

13 hours ago, rob_ess said:

ok so there are two. are they both the same or is one a 2 wire and other a 4?

i figured if it was the cat, the code would be steady. my "check engine" light is off again. it will pop on once in a while and then go back off after however many start. That has always happened with 02 sensors for me.

i tried to get a temp reading from the manifold side and the after the cat but i can't get a consistent reading before the cat. Maybe too much residual heat? I'll start with the sensors. 

Thanks, everyone.

 

Rock auto lists the same sensor for both upstream and downstream. 4 wire. Along with autozone, advance, etc. 

[rob_ess]

3 hours ago, jkeaton said:

 

Rock auto lists the same sensor for both upstream and downstream. 4 wire. Along with autozone, advance, etc. 

Perfect. Thanks!

[A Sweeten]

If I need to replace the cat, does it have to be OEM or can it be a generic replacement one to get the 0420 code to go away? or is there a easier way?

 

[larryl]

0420 code can be hard to diagnose engine size matters also and this is a 6 yr old thread.