CEL Code P0420: Cat converter going bad?

[98FordLove]

I keep getting the CEL popping up with this code - P0420. It started about a year ago and then I cleared it and it came back on just a couple of weeks ago. It says that there is an issue with the cat convertor. The first time it popped up, I tried cleaning it with over the counter cleaner and running a tank of premium gas and nothing black came out of the exhaust. So I'm wondering if I keep driving it like this, will it be bad for the truck? My mech says it won't be but just want to make sure. Thanks.

I was told by someone else to just cut the cat out? I'm pretty sure a lot of people with older cars have this same code but just leave it as is. I'm just wondering how long it will be before a cat usually goes bad?

 

[Fix4Dirt]

depends, is it making it lean or rich? it could have other effects. the cat itself wont affect anything else, but it could have side effects imo. cutting he cat out is an option, but it creates more pollution and wont pass smog. there are replacement cats available on rockauto.

 

[Stynx]

In the US it's against federal law to remove the cat IIRC. Dunno about Canada but I'd check around first.

 

[C420sailor]

Don’t cut your cats out unless you want a permanent CEL.

That code (for the downstream sensors) can be tripped if the upstream sensors are starting to go. I’d check your live data, make sure your upstream O2 sensors are functioning accurately and your fuel trims are good. If that all checks out, I’d try throwing downstream sensors at it, especially if their readings are obviously boned.

Downstream sensor codes don’t affect how the truck drives, just sets the CEL.

Unless the truck has been running very rich for a long period of time, the cats themselves are prob fine

 

[98FordLove]

depends, is it making it lean or rich? it could have other effects. the cat itself wont affect anything else, but it could have side effects imo. cutting he cat out is an option, but it creates more pollution and wont pass smog. there are replacement cats available on rockauto.

How do I tell if it's running lean or rich? Don't really want to spend money on something expensive like a cat if I can avoid it.

 

[Fix4Dirt]

How do I tell if it's running lean or rich? Don't really want to spend money on something expensive like a cat if I can avoid it.

forscan+ELM adapter

 

[98FordLove]

Don’t cut your cats out unless you want a permanent CEL.

That code (for the downstream sensors) can be tripped if the upstream sensors are starting to go. I’d check your live data, make sure your upstream O2 sensors are functioning accurately and your fuel trims are good. If that all checks out, I’d try throwing downstream sensors at it, especially if their readings are obviously boned.

Downstream sensor codes don’t affect how the truck drives, just sets the CEL.

Unless the truck has been running very rich for a long period of time, the cats themselves are prob fine

I had my sensors checked last year and they were fine but I even changed all three o2 sensors just in case. Turns out it was a waste of money. What I don't get is that it put out the sensor for the cat for about 8 or 9 months but then it comes back WTF?

 

[Fix4Dirt]

put out? do you mean that the sensor only lates 8-9 months? if do, which brand?

 

[98FordLove]

put out? do you mean that the sensor only lates 8-9 months? if do, which brand?

I put in all new sensors about 12 or 13 months ago. All NGK brand. The CEL just randomly went out today but it will eventually come back on.

 

[drdoom]

If that is the code for "catalyst effeciency below threshold", sensors will take care of it.
As posted above, live data is the way to go.
But prior to learning that, I used a propane torch and a multimeter.
16 years and 120,000 miles still no problems.