I got a (Catalic system efficiency below threshold) code on my 4cyl 98 accord with 82,000 miles. I assume this is from a bad O2 sensor or the converter is clogged. Does anyone know the best way to diagnose the actual cause of this code? I got the code before my car hit 80,000 but some mechanic that did my tires cleared it with out asking and now the code has come back after 80,000. However I have an invoice showing original date and miles the code appeared. Is their a way to qualify for the federal 8/80 warranty on emisions or should I fix this myself.??? Please offer any advice you might have. Thanks

 

my light is also on. Its not much of a problem, just a bad o2 sensor in ur cat. The light does turn off sometimes for me, but i'm planning to cut the sensor off, plug the bung up with a bolt and use a o2 similator. That sensor alone is about $120.

 

I do not want to "rig" a solution for my problem. I want it fixed the right way. I need to know how to determine if it is the o2 or the converter. $120 does not seem like much if it keeps your car runnig like it was designed for. Can anyone ofeer any GOOD advice.

 

try taking it to a shop and test the sensor. no need to beat this situation around the bush if it's a big problem. If the sensor does not regesiter within the voltage, then it is the sensor. If the sensor registers, then it is ur cat. Good luck.

 

Sounds Good. Is their a way to test the sensor myself with a multimeter?
Thank You

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by trocks &raquo;</TD></TR><TR><TD CLASS="quote"> I need to know how to determine if it is the o2 or the converter. </TD></TR></TABLE>
If it's a code p0420, it's almost always a bad cat.