Toyota Nation Forum banner

1 - 7 of 7 Posts

·
Registered
Joined
·
22 Posts
Discussion Starter · #1 ·
Thanks in advance for your tips

My son's 2002 corolla threw a CEL, I scanned it with a bluetooth OBD2 scanner (paid Torque app) and got two codes:
Current Fault = P0420 - Powertrain
Catalyst System Efficiency Below Threshold (Bank 1)
Pending Fault = P0446 - Powertrain
Evaporative Emission Control System Vent Control Circuit

Very rudimentary testing on my part so far.

I used the Infrared Thermometer and measured the temp. before and after the catalytic converter when the car was fully warmed up. It seems to be okay, 275F on the pipe just in front of the CC and 380F just behind.

The app can show raw data from the sensors but I'm not sure it's real time because it updated very irregularly, like every 2 secs. I drove it around fully warmed up and asked a pass. to read out the upstream and downstream values. The Upstream bounced around but largely stayed around .7 to .9 (sometimes dipping to .2 but rarely) the downstream one copied the upstream .7 to .8V (it did drop to .2 as well when I let up on the gas(?))

Here's the history: The cel came on after I did an engine swap. I took out an engine that had ring failure (so I suspected a clogged cat) but it might also be that I reused the gasket for the upstream O2 sensor? The nuts are tight but maybe it leaks(?). I've been hesitant to buy just the gasket since it sells for $20 and a Denso sensor+gasket is $60.

The attached picture is from the app after the ride.
 

Attachments

·
Moderator
2012 corolla ce
Joined
·
1,558 Posts
1) try rockauto.com
2) your p0420 can be fixed for $8 with a non fouler just Google it and you will see
3) the p0446 is likely the solenoid on the charcoal canister. Just a warning it's the dirtiest place on Earth so mask up before you get in there. Jump the power to the solenoid and see if you can hear it open and close if it's sluggish or slow replace it and all will be well.
 

·
Registered
Joined
·
22 Posts
Discussion Starter · #3 ·
Thanks for the suggestions.

Fixing the problem is money well spent too. I'm not averse to the anti-fouler; I'd just like to try to fix it first.
If I probe the signal wire of each sensor I should get a better idea of what each sensor is doing, No?
I've read though that the P0420 is a pretty reliable code for a bad cat...
 

·
Registered
2000 Toyota Corolla
Joined
·
144 Posts
Thanks for the suggestions.

Fixing the problem is money well spent too. I'm not averse to the anti-fouler; I'd just like to try to fix it first.
If I probe the signal wire of each sensor I should get a better idea of what each sensor is doing, No?
I've read though that the P0420 is a pretty reliable code for a bad cat...
In a lot of cases 420 is a bad cat, or rather below efficiency threshold. Sometimes it is the O2 sensor related.

The thing is with cats, don't waste your money on an aftermarket one. They have insignificant amounts of platinum, palladium, etc. I've cut open tens of thousands of cats (former job), some of the aftermarket ones sort of have a spark plug non-fouler effect and that's how they "work", only for X50 the cost. Other aftermarket cats have very minimal amounts of precious metals. Enough to get you pass a test and then they bight the dust. Don't waste $200 or $300 dollars on the junk. It's basically a scam.

The other option for a catalytic converter is OEM. They're expensive, but they work.
 

·
Registered
Joined
·
22 Posts
Discussion Starter · #5 ·
tbh I was looking at a CARB compliant Magnaflow, of all the horror stories(and there are a ton) of aftermarket cats, they seem to have the fewest failures? It's $180 compared to $80 for a non-CARB aftermarket or $1300 for the oem.
 

·
Registered
2000 Corolla
Joined
·
54 Posts
1) try rockauto.com
2) your p0420 can be fixed for $8 with a non fouler just Google it and you will see
3) the p0446 is likely the solenoid on the charcoal canister. Just a warning it's the dirtiest place on Earth so mask up before you get in there. Jump the power to the solenoid and see if you can hear it open and close if it's sluggish or slow replace it and all will be well.

Wow I have never heard of that Non Fouler Trick before! So is that just to trick the computer into not throwing a code even though you have a bad Catalytic Converter? In order to then pass an emissions test? I can see the benefit for quickly passing an emission test, but don't you need to replace the Cat eventually anyways?

Seems like that was what this guy did in this video
 

·
Registered
Joined
·
132 Posts
I've heard that the Magnaflow brand are just fine. If it turns out that it really is the catalytic converter, you can get model 51204 and have your local shop cut out the old and weld the new one in. I think it cost me only an additional $60 bucks for that labor, but I live in a pretty low-cost area. I've heard of difficulties installing the bolt-in units because of things not lining up just right in many cases (and they're a few hundred bucks).
 
1 - 7 of 7 Posts
Top