Is your car a California model? If the right converter wasn't put on in the first place. That would cause your issues. Look under your hood for the emissions sticker. If that doesn't work, call the dealer with your vin ready.


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Is your car a California model? If the right converter wasn't put on in the first place. That would cause your issues. Look under your hood for the emissions sticker. If that doesn't work, call the dealer with your vin ready.


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No I do not believe it is a CA model.

 

Was it P0420?... Catalyst System Efficiency Below Threshold (Bank 1)

They'll sometimes they'll throw that code if the downstream O2 sensor is bad. The ECU compares the output of upstream and downstream sensors and if the exhaust is not cleaner after passing thru the cat, it sets that code. So a flaky downstream sensor can definitely be the cause. And it's somewhat common.

Can this one code be permanently disabled or perhaps the computer modified so a satisfactory reading is obtained?

No, not easily anyway. It would be simpler to fix what's wrong.

 

Was it P0420?... Catalyst System Efficiency Below Threshold (Bank 1)

They'll sometimes they'll throw that code if the downstream O2 sensor is bad. The ECU compares the output of upstream and downstream sensors and if the exhaust is not cleaner after passing thru the cat, it sets that code. So a flaky downstream sensor can definitely be the cause. And it's somewhat common.

Yes I believe that was the code? When you say downstream O2 sensor. That is a sensor outside of the catalytic convertor?

 

Not sure what you mean by "outside"? Yes, it's not inside the cat, if that's what you're asking. It's screwed into the exhaust pipe, just downstream from the cat. Crawl under and have a look, it's hard to miss.

 

Thanks. I have not worked on my own vehicles for years. Is this something I should be able to replace on my own? Will it be hard to remove?

Will the code clear once replaced (assuming this is the issue)?

 

It's not extremely difficult to replace, but it depends on what you're comfortable with. Here's a DIY thread showing how to do it... http://www.toyotanation.com/forum/1...ion-1992-1996-1997-2001/197633-diy-downstream-oxygen-o2-sensor-replacement.html

The code will clear itself if the repair is successful. If you want, you can clear them by pulling & reseating the EFI fuse in the fusebox under the hood, rearward of the battery.

 

Thanks for the help. Funny it went off all by itself and has stayed off. Not sure if it means anything but the day the light went off, it was a bit warmer around here then it has been. But it has gotten colder again and it is still off.