Can a bad O2 sensor indicate a bad cat?
A bad O2 sensor will indicate that the catalytic converter is bad. If the code indicates a bad cat…then further tests need to be run to determine if it’s a bad O2 sensor or a bad cat. Good mechanics know how to do this. Cavell July 6, 2016, 3:57am #12 I assume next argument will concern using oem cat or aftermarket cat and/or new oxy sensor.
What should I do if my O2 sensor is not working?
First check for exhaust leaks – that’s a common cause for an O2 sensor related codes. If that’s not it, follow the other guys’ advice and replace the appropriate O2 sensor (likely the post CAT sensor) first and see if that fixes the problem.
What happens to the sensor in a catalytic converter?
This will result in the sensor output of little or no voltage. Usually 0.2 volts or less. A fully fueled misfire such as is seen when fuel is injected but spark fails will result in a fuel air mixture exiting the cylinder and thus being burned in the catalyst.
How is post Cat O2 used to diagnose misfires?
I’ve been researching using pre and post cat O2 waveforms to diagnose misfires and ran across this quote from the article, Intermittent Engine Misfire Analysis: Keep in mind that the downstream, post-catalyst oxygen sensor can often be used to differentiate between an ignition- or fuel-related misfire.
A bad O2 sensor will indicate that the catalytic converter is bad. If the code indicates a bad cat…then further tests need to be run to determine if it’s a bad O2 sensor or a bad cat. Good mechanics know how to do this. Cavell July 6, 2016, 3:57am #12 I assume next argument will concern using oem cat or aftermarket cat and/or new oxy sensor.
How are O2 sensors and catalytic converter diagnostics fail?
O2 SENSORS & CATALYTIC CONVERTER DIAGNOSTICS Converters typically fail one of two ways: they get too hot, melt and plug up, or the catalyst becomes contaminated and useless.
First check for exhaust leaks – that’s a common cause for an O2 sensor related codes. If that’s not it, follow the other guys’ advice and replace the appropriate O2 sensor (likely the post CAT sensor) first and see if that fixes the problem.
Why is the rear O2 sensor behind the light-off catalyst lazy?
The O2 sensor behind the light-off catalyst (the Downstream Sensor) is also monitoring oxygen, but if the light-off (NOx) catalyst is storing oxygen properly (meaning the catalyst is healthy), the rear O2 sensor signal will be very lazy when compared to the upstream O2.