P0420 code Converter Code? 2008/110,000 miles

[Sarasmiles]

Oh Joy,,
Engine light came on today.

Did the Key Dance,
No Code Displayed then " done "

Symptoms
No misfires,
No Noises
No sounds like air leaks
No abnormal exhaust noise
Runs like silky smooth
Average gas mileage unchanged
In other words, the car is running flawlessly

I did a search, found an interesting article posted here;
Diagnose P0420 Catalyst Code

Also this one.
P0420 DTC Code - Catalyst System Efficiency Below Threshold (Bank 1)

Can anything else cause this code?
Should I go aftermarket on a new cat?

What is suggested/reccomended?

Sara

[quicksilverdon]

There are times a misfire trips the engine light but doesn't last long enough to store a code.
If you have no code and engine is running fine, don't sweat it. Just check every so often that you still have no code and light will go out on it's own.
I have not read of many needing a new converter.

[Sarasmiles]

Originally Posted by quicksilverdon

There are times a misfire trips the engine light but doesn't last long enough to store a code.
If you have no code and engine is running fine, don't sweat it. Just check every so often that you still have no code and light will go out on it's own.
I have not read of many needing a new converter.

Maybe I should reword the post.

When I get the code read with a code reader, it pulls up P0420
The engine light is still on.

IF I do the PT key dance to check for codes, it says done.

Is P0420 a code that the key dance does not read?

[CREWZIN]

According to this link, it could be one of your 02 sensors.

2001 Chysler Pt Cruiser

[pappasmurf]

It is your car not reading your cat. Same EXACT code I was getting when I removed my cat. Get an aftermarket cat and before it is welded on, turn the car on and see if it clears the code. If it does, go ahead and weld. If not just have the mechanic weld 2 sparkplug foulers in line with the pipe and remove the cat completely.

[Sarasmiles]

OK More weirdness,

Now the lights off, and the code is cleared?

It happened this morning, went off to go to work,, no check engine light.
Went back to Advanced for a free code read again after work,,
Nothing!

Maybe it was just a glitch?
Beats me.

With the Check Engine light on the Key dance showed no codes.
The Code reader at Advanced clearly showed P0420, he checked it several times restarting between each test.

Tonight, it shows no error code.

Guess I'll just ignore it for now.

[Sarasmiles]

Well, that was a short ignore. Today the light came back on. Exact same scenario, Onboard code read says nothing except "done". Plug in a code reader under the dash, same error P0420.
Seeing as its intermittent I'll have to have someone get it up on a rack and check it out I guess.

Will post results as soon as I get some answers.

Sara

[Sarasmiles]

So,,, about 8 weeks ago I had to replace my camshaft sensor again as it started to fail (code confirmed).
Took a Mopar out,, put another Mopar in.

We were still having the p0420 code prior to the change.
So anyway, after I put the sensor in, I reconnected the battery and all was good. No codes at all for 8 weeks.

Oddly the p0420 code seemed to have stopped, at least until today. 1st time in months!

This is an intermittent issue I suppose, but sure annoys.

[767skyking]

Had this problem... had to put a new cat in.. Works fine now!