P0420 code

[Tony's backyard]

When you get code P0420 catalyst system efficiency below threshold bank1. How to find this problem? Need help pls.

[tmontague]

How many km's on the car? Need a bit more info. Burning any oil between oil changes?

This means that the cat is either very dirty, semi plugged or insides are broken to where it is working less than 95% efficiency (that triggers the CEL).

Burning excess oil can foul the cat causing this. Generally only solution is replacing the cat, but you need to fix the issue of why this happened first so it doesn't happen again.

My '02 Echo has this code. I was able to still get it past emissions using my ultragauge, seafoam and understanding that one system check can still be not ready and it can still pass

[Tony's backyard]

It's a 173,a bit km no burning oil running still good

[Tony's backyard]

Actually I found 2 more code clear all the code but come back after 4 days. It's always come together 3 code P0420,P0441and P0455. Change fuel cap and also I check purge valve solinoid working the way it should. Car run fine. Why 3 code always coming together? Any one encounter this before? Pls. Need help

[CTScott]

0420: Catalyst System Efficiency Below Threshold (Bank 1)
Causes:
- Front exhaust pipe (with Three-Way Catalytic
Converter)
- Gas leakage from exhaust system
- A/F sensor (sensor 1)
- HO2 sensor (sensor 2)

0441: Evaporative Emission Control System Incorrect Purge Flow
Causes:
- Purge VSV
- Connector/wire harness (Purge VSV - ECM)
- Canister pump module
- Leakage from EVAP system
- Leakage from EVAP line (Purge VSV - Intake
manifold)
- ECM

0455:Evaporative Emission Control System Leak Detected (Gross Leak)
Causes:
- Fuel cap (loose)
- Leakage from EVAP line (Canister - Fuel tank)
- Leakage from EVAP line (Purge VSV -
Canister)
- Canister pump module
- Leakage from fuel tank
- Leakage from canister

[Tony's backyard]

Thanks for all info. Start checking for the possible problem. One more thing come out air bag on. I read the procedure to check for air code for 06' yaris. It is the same for 07' jumper tc + cg to get code for air bag

[Tony's backyard]

Is this 3 code I'm getting is all related cuz is always coming together

[Bluevitz-rs]

I have the P0420 code now after turbocharging my car. I built a new full 2" exhaust using the stock Cat. I never got this code before on my old engine. Is it possible the Cat simply isn't getting as hot now? Because the entire turbo system is built from very heavy schedule 40 weld together piping. I haven't wrapped it yet but will be doing that soon at my next oil change.

[CTScott]

Originally Posted by Bluevitz-rs

I have the P0420 code now after turbocharging my car. I built a new full 2" exhaust using the stock Cat. I never got this code before on my old engine. Is it possible the Cat simply isn't getting as hot now? Because the entire turbo system is built from very heavy schedule 40 weld together piping. I haven't wrapped it yet but will be doing that soon at my next oil change.

Have you tuned for the Turbo yet? It is also possible that you are running way too rich.

[Bluevitz-rs]

It's running on stock numbers out of boost 95% of the time. Only past 1psi that there any mods to fuel and timing. So it runs 14.7afr out of boost.

I've got new plugs to go in too when I change the oil and wrap the pipes.

Only reason I'm thinking it's not hot enough to is that the stock exhaust before the Cat was a double wall pipe and that would definitely keep the heat in.

[CTScott]

Originally Posted by Bluevitz-rs

It's running on stock numbers out of boost 95% of the time. Only past 1psi that there any mods to fuel and timing. So it runs 14.7afr out of boost.

I've got new plugs to go in too when I change the oil and wrap the pipes.

Only reason I'm thinking it's not hot enough to is that the stock exhaust before the Cat was a double wall pipe and that would definitely keep the heat in.

That is definitely possible. Do you perchance have a diagnostic device that will let you watch the sensor data from the two O2s?

[Bluevitz-rs]

Yeah got a nice one for Xmas.

The front O2 sensor is fairly new but the secondary is still original.

Unfortunately my AEM AFR sensor failed in under 3000km and they wouldn't replace it so I've been unable to monitor the AFR for a few months.

[Bluevitz-rs]

Monitored the Sub O2 in the driveway today after a short drive to heat everything up. Holding at 2000 rpm the reading was pretty steady at .780-.820V. With the occasional dip and then back up. At idle it bounces back and forth almost the same as the primary but a bit slower.


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[CoryM]

Thats the results of a "good" cat. It's possible that your cat is border-line and only fails occasionally. It's also possible that your exhaust has an air leak sometimes, or that the turbo is running too much exhaust for the OE cat to handle.

[Bluevitz-rs]

I had JUST added heat wrap to the downpipe and just in front of the Cat too so time will tell I suppose. The freeze frame data showed the last time it set a code I was cruising at 2200 rpm at 65km/h and light load. But that was with old plugs and no heat wrap.

[Bluevitz-rs]

Well, two trips and no pending code and the readiness test on my scan tool show the cat as ready, so I'm a happy camper.

I'm thinking it was my plugs being slightly damaged from running lean in boost when I first built my turbo system. I reused my old plugs from the old engine. I replaced them with one step cooler plug this go around and left the gap they came with at .038"