P0420 code - Suggestions?

[Kelemvor]

So I have an '01 Camry I recently bought from a friend. About a month ago the Engine light came on. I didn't worry about it and a week later it went off. Then about a week after that it came back on again. I think when it went off it was just after getting gas or something if that matters.

Anyway, it's been on for a couple weeks now and hasn't gone back off. I took it to Autozone and they read the P0420 code.

Definition: Catalytic system efficiency below threshold - bank 1

Probable cause:
1 - Air leak in exhaust before rear H02S (Heated Oxygen Sensor) Bank 1
2 - AF sensor error
3 - Fuel system fault
4 - Faulty catalytic converter

I was hoping this was something easy like replacing the gas cap or something like that.

I don't know anything about this car since I've had it for only 2 months or so. Can anyone recommend what the "normal" thing that would cause this is? What things should I do in what order? Is this something I can easily do myself?

I don't really have the cash to pay a mechanic hundreds of dollars to figure it out and I have to have emissions done in under a week to finish the registration process.

Any help would be great.

Thanks!!

[CarryMeBF]

Originally Posted by Kelemvor

So I have an '01 Camry I recently bought from a friend. About a month ago the Engine light came on. I didn't worry about it and a week later it went off. Then about a week after that it came back on again. I think when it went off it was just after getting gas or something if that matters.

Anyway, it's been on for a couple weeks now and hasn't gone back off. I took it to Autozone and they read the P0420 code.

According to their print out, the normal culprits are:
1 - Air leak in exhaust before rear H02S (Heated Oxygen Sensor) Bank 1
2 - AF sensor error
3 - Fuel system fault
4 - Faulty catalytic converter

I was hoping this was something easy like replacing the gas cap or something like that.

I don't know anything about this car since I've had it for only 2 months or so. Can anyone recommend what the "normal" thing that would cause this is? What things should I do in what order? Is this something I can easily do myself?

I don't really have the cash to pay a mechanic hundreds of dollars to figure it out and I have to have emissions done in under a week to finish the registration process.

Any help would be great.

Thanks!!

Is the gas cap all the way on?

If that is not it, then I may just say (though I'm not sure) that it would be one of your oxygen sensors (1 of mine went out at 137k miles) though I hope you can get a better reading before you go and change that bc they cost $150 (you can do that yourself). But the tester you should be able to see words next to the code, odd. Autozone near me doesn't come out and do it for you, you use it yourself. I used the code reader and it had words next to the number to give you a general idea of what is the problem.

EDIT: I just searched on google: P0420 code on toyota camry 2001 I encourage you to do it so you can see the responses that I saw. They seem to think it is typically the catalytic converter, but I'd find someone more reputable than autozone or friend has a code reader to help you read the code. But again make sure the gas cap is on tight.

[Kelemvor]

Originally Posted by CarryMeBF

Is the gas cap all the way on?

If that is not it, then I may just say (though I'm not sure) that it would be one of your oxygen sensors (1 of mine went out at 137k miles) though I hope you can get a better reading before you go and change that bc they cost $150 (you can do that yourself). But the tester you should be able to see words next to the code, odd. Autozone near me doesn't come out and do it for you, you use it yourself. I used the code reader and it had words next to the number to give you a general idea of what is the problem.

EDIT: I just searched on google: P0420 code on toyota camry 2001 I encourage you to do it so you can see the responses that I saw. They seem to think it is typically the catalytic converter, but I'd find someone more reputable than autozone or friend has a code reader to help you read the code. But again make sure the gas cap is on tight.

Yes, the gas cap is on tight. I always turn it until it starts clicking a bunch. Places around here don't let you use the devices yourself any more because they get fined if you reset the code when the problem isn't really fixed. I forgot the "Definition" in my OP so I'm adding that up there.

The guy at Autozone didn't think it was the catalytic converter unless I was having a fuel problem as well.

[Dave's]

How timely. Just had the same code on my wife's '01 yesterday. Reset it and it's not back yet. However, I'll probably replace the O-ring on the gas cap before anything else. They CAN go bad and no matter how many times it clicks the seal won't hold. Here's hoping...

[Pvt-Public]

On my 1999 5S-FE it took replacing both O2 sensors. And have not had a code in over a year now.

[Woodyg]

Originally Posted by Kelemvor

So I have an '01 Camry I recently bought from a friend. About a month ago the Engine light came on. I didn't worry about it and a week later it went off. Then about a week after that it came back on again. I think when it went off it was just after getting gas or something if that matters.

Anyway, it's been on for a couple weeks now and hasn't gone back off. I took it to Autozone and they read the P0420 code.

Definition: Catalytic system efficiency below threshold - bank 1

Probable cause:
1 - Air leak in exhaust before rear H02S (Heated Oxygen Sensor) Bank 1
2 - AF sensor error
3 - Fuel system fault
4 - Faulty catalytic converter

I was hoping this was something easy like replacing the gas cap or something like that.

I don't know anything about this car since I've had it for only 2 months or so. Can anyone recommend what the "normal" thing that would cause this is? What things should I do in what order? Is this something I can easily do myself?

I don't really have the cash to pay a mechanic hundreds of dollars to figure it out and I have to have emissions done in under a week to finish the registration process.

Any help would be great.

Thanks!!

you are in a pickle between the time restraints and financial restraints........have you had the initial inspection already and failed the emissions part and they give you 60 days to fix it?

It could be a few things as stated....if the car runs perfectly fine my guess might be the rear O2 sensor. The rear O2 sensor virtually has no control over engine management thus if the car runs fine it could just mean that the rear sensor is toast.........but it is just a guess without seeing any PID's.......I would clear the code and hope it does not come back until you inspect it...........I solve a lot of issue like this with my cheap codereader.......a lot of times the cars will have a pending code that does not set of the CEL.......if you catch one of these it might help pinpoint the issue.......you can buy cheap code readers for $30

[Kelemvor]

I did pull the battery cable off the negative terminal this morning which reset the code (and other things). I recorded my mileage and will see how it goes. I know that if you go to emissions and don't have enough miles on since a code went away, they can tell that and can fail you.

However, no, I have not gone for emissions yet since I knew it was going to fail. If the light comes back on, I'll just take it over anyway, get the failure, and then worry about fixing it.

I also reseated the gas cap in case that had anything to do with it. I don't notice the car running poorly but I've only had it for 2 months so I'm not in tune with it yet. I guess we'll see what happens.

[Woodyg]

Originally Posted by Kelemvor

I did pull the battery cable off the negative terminal this morning which reset the code (and other things). I recorded my mileage and will see how it goes. I know that if you go to emissions and don't have enough miles on since a code went away, they can tell that and can fail you.

However, no, I have not gone for emissions yet since I knew it was going to fail. If the light comes back on, I'll just take it over anyway, get the failure, and then worry about fixing it.

I also reseated the gas cap in case that had anything to do with it. I don't notice the car running poorly but I've only had it for 2 months so I'm not in tune with it yet. I guess we'll see what happens.

in my state if you flunk the emissions you can still drive the car for 60 days while getting it fixed..hopefully you have a similar law...... I did some googling for you and saw a few posts that said you might have a TSN for that p0420 code......the fix was to reflash the puter.........also sometimes if the CAT is toast it will GLOW........my guess is the CAT, the rear O2 or a reflash.....

[Kelemvor]

Originally Posted by Woodyg

a few posts that said you might have a TSN for that p0420 code......the fix was to reflash the puter.........also sometimes if the CAT is toast it will GLOW........my guess is the CAT, the rear O2 or a reflash.....

OK, you lost me o nthe above part. What's a TSN? what gets reflashed? And what will glow exactly?

[Woodyg]

Originally Posted by Kelemvor

OK, you lost me o nthe above part. What's a TSN? what gets reflashed? And what will glow exactly?

sorry my bad.....I meant to type TSB

-TSB-technical Service Bulletin

-reflashing=reprogramming the ECU, The ECU is the computer for the car(sometimes they do this for free on a TSB other times it costs $75-$100)

-if the CAT=Catalytic Converter is ruined it can get hot and GLOW after you have driven the car.

[BamZipPow]

You could have a vacuum leak in one of yer hoses as well. A smoke test can reveal where you have leaks.

[Kelemvor]

Well, I popped the battery end off to rest the code Thursday before work. It was still off today so I went in at lunch to get it tested. I passed.

On my way back to work, the light came back on.