1999 Toyota Corolla Catalytic Converter

1999 TOYOTA COROLLA
128,000 MILES • 4 CYL • 2WD • AUTOMATIC
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SFOLK
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My check engine light came on, and upon testing, I was told that something connected with my catalytic converter could be the issue. Anywhere from a sensor, to oil leakage. How do I know? What kind of test can I get done to determine the exact issue?
Feb 26, 2009 at 1:01 PM
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MMPRINCE4000
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You can have the convertor tested, by a backpressure test, which will tell you if the convertor is clogged.
Generally the error code is generated by a bad O2 sensor. There are at least 2, one upstream (before convertor) and downstream (after convertor).
The PCM is programmed to compare the reading from the two, looking for a specific accecptable "range". If out of range the PCM will set an error code.

A dealer or trusted garage has more sophiscated scanners that can test the sensors and give you a more accurate diagnosis than autoparts stores can.
Feb 26, 2009 at 4:01 PM