Engine Light Came On - Help Pls

[USMC11]

Hey Everyone,

So my engine is throwing a code P0420 (yes, I thought it might have the munchies too...). On the list I have, the code reads as 1/1 Catalytic Converter Efficiency.

The code came on yesterday and I reset it and then it came back on today.

I'm guessing it's either the sensor or the cat itself. The truck has 48k miles and is a 2004. Seems soon for the cat to be going out. I just changed the exhaust about a month ago, could that have caused this?

Does this do anything to engine timing or make the truck run rich? Also any tips on how I should go about fixing this?

Any help on this would be greatly appreciated gents.

 

[TNVIPER]

Cats generally last the life of the vehicle but can go bad at any mileage...

I assume you left the cats on when changing the exhaust...may just be a loose conection or maybe a bad sensor.....Your dealer can check these...

As long as the light is not flashing there is no damage being done. If the lights flashes the engine needs to be stopped as soon as possible....otherwise take it in when you can...

 

[VIPR PWR]

may or may not pertain but here it is anyway...My Dakota has that code on and off----I found that during the hot times, running the A/C that the condensation drain tube is dripping and the water runs down the wires onto the o2 sensor ---when the A/c is off for a couple of days it resets and the light goes off.... I tried moving the drain tube , but it continues to find it's way back....I live with it for now...it does not seem to affect the running of the engine..

 

[USMC11]

Cats generally last the life of the vehicle but can go bad at any mileage...

I assume you left the cats on when changing the exhaust...may just be a loose conection or maybe a bad sensor.....Your dealer can check these...

As long as the light is not flashing there is no damage being done. If the lights flashes the engine needs to be stopped as soon as possible....otherwise take it in when you can...

With that code it could be a bad sensor? Aren't there separate codes for that?

I understand that the dealership is required to warranty cats up to 80k miles up to 8 years..maybe ill just take it there. I hate to do that tho cause I'm a cheapskate just in case they try to charge me for something lol

 

[TNVIPER]

With that code it could be a bad sensor? Aren't there separate codes for that?

I understand that the dealership is required to warranty cats up to 80k miles up to 8 years..maybe ill just take it there. I hate to do that tho cause I'm a cheapskate just in case they try to charge me for something lol

The sensor could be bad as in sending inaccurate readings. In this case the PCM would assume the sensor is working and the cat is the problem. If the sensor quit working then yes, you would get a sensor code.

Best option is to take to the dealer. The cat could be damaged and restricting airflow..