Intermittent CEL
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Joined: Aug 2001
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From: New York City, Amagansett, N.Y.
Intermittent CEL
In June 2008 I had some AWE cats installed. About a month ago the CEL came on. A friend with an OBDII reader checked and the code P0420, Bank 1 Above Limit TWC Conversion came up. AWE claims its not a cat issue but an 02 sensor issue. (The cats are still under warranty.)
About a week later and 200 miles, the light went off. Two weeks later and 400 miles, light came back on. A few days later and about 150 miles, light off again.
Any thoughts from the resident experts as to what's happening and the solution?
About a week later and 200 miles, the light went off. Two weeks later and 400 miles, light came back on. A few days later and about 150 miles, light off again.
Any thoughts from the resident experts as to what's happening and the solution?
Race Director
Joined: Sep 2006
Posts: 19,031
Likes: 266
From: Bentonville, AR
In June 2008 I had some AWE cats installed. About a month ago the CEL came on. A friend with an OBDII reader checked and the code P0420, Bank 1 Above Limit TWC Conversion came up. AWE claims its not a cat issue but an 02 sensor issue. (The cats are still under warranty.)
About a week later and 200 miles, the light went off. Two weeks later and 400 miles, light came back on. A few days later and about 150 miles, light off again.
Any thoughts from the resident experts as to what's happening and the solution?
About a week later and 200 miles, the light went off. Two weeks later and 400 miles, light came back on. A few days later and about 150 miles, light off again.
Any thoughts from the resident experts as to what's happening and the solution?
The Ecu uses the O2 sensor readings before and after the converter to test its oxygen storage capability.
If the sensor readings indicate the converter is not storing enough oxygen this is a sign the converter is aging.
However, the P0420 (or P0430) error(s) can be accompanied by O2 sensor aging error(s). If so, the recommendation is to replace the sensors id'd by the error codes, clear the codes, and test drive the car.
Absent any O2 sensors aging error codes I'd have to say the converter on that side is not performing up to par.
However, with an aftermarket exhaust or the stock exhaust with modifications this raises the possibility of an exhaust leak that can affect the sensor readings.
As always, then, the first just is to make sure the exhaust system is air-tight that no outside air can get in and no exhaust gases can escape.
If the exhaust system checks out ok then if you want you can swap the #2 sensors (the ones after the converters) with each other and see if the error code follows the sensor or stays with the converter.
Sincerely,
Macster.
