driving with a P0420

[CELICA XX]

2002 Toyota ECHO
1NZ-FE (1.5 L)
5-speed

163k

I am currently in the process of properly diagnosing a P0420 code in my car. It just appeared a last week. I cleared the code and it came back two days later. The car runs perfectly, no drivability issues.

Is it safe to keep driving it while I get things sorted out ?

Specifically, I have a 1000 mile trip coming up.

Thank you.

Topic

[Wayne]

Yep, other than throwing a bit more garbage into the air, you should be fine. Nearly always means the cat is just done, so long as you noted no drive-ability/performance issues, likely just due to normal wear. If it failed under 100k I’d suspect it was perhaps in need of an o2 sensor, or otherwise a diagnosis for premature failure (usually due to rich condition).

Heard at least one recover it from just detergent and water(hot at start I believe), so long as the substrates are intact, mix it around a bit when you can, let it soak for a day. Not sure how long it’ll last, but even another 20k would be awesome. Really unless you’re dead broke for a time, best to just wait, spend the money on a replacement, and only have to mess with it once IMO. Usually find direct fits after-market that aren’t much over $200 for anything but euro vehicles. Just get one that actually stands behind it for more than a short duration.

If you have any concerns you could just verify the fuel trims, make sure they aren’t too far off, but 160k+ is a good run on the original cat.

http://www.autotap.com/techlibrary/catalytic_converters_and_o2_sensors.asp

If the problem may cause emissions to exceed 1.5 times the federal limit, the Malfunction Indicator Lamp (MIL) will come on and the PCM will log a diagnostic trouble code for “catalyst is below threshold efficiency” (P0420, P0421, P0422, P0430, P0431 or P0432). The bottom line here is you have a bad converter — unless the problem is something else like a bad oxygen sensor or open fuel feedback control loop.

[EricTheCarGuy]

Yes and no. If the catalytic converter isn’t functioning because the catalyst is dirty that’s one thing, but if it’s starting to clog up it can cause performance and drivability issues. You can easily check for an exhaust restriction however using this method.

You can diagnose the converter this way.

And you might be able to clean it. Just use more lacquer thinner than I did. I didn’t use enough in this video. The best way to clean is with soap and water I believe but I have yet to try that.

Keep us posted and good luck.

[Author]

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