Is it my O2 sensor or catalytic converter?
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.
Can a bad O2 sensor cause catalytic converter code?
Can a bad O2 sensor cause a P0420 code? Yes. As such, failure of either the upstream or downstream oxygen sensor can cause code P0420 to set. The most common cause of the code, however, is a failed catalytic converter.
What are the symptoms of a bad catalytic converter oxygen sensor?
First, what are the signs an O2 sensor may have gone bad?
- Check Engine Light Comes On.
- Noticeable Loss of Fuel Efficiency.
- Sulfur or ‘Rotten Egg’ smell from Exhaust.
- Black smoke from exhaust.
- Emission levels reach high levels.
- Your engine hesitates, skips, begins bucking or has power surges.
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.
What does the sensor on the catalytic converter do?
The downstream oxygen sensor, on the other hand, should show very little movement. It’s testing the catalytic converter to see if it’s storing oxygen during rich events and then using the oxygen during lean events.
Why is my OBD not working on my catalytic converter?
The OBD II system can’t evaluate the converter if the upstream and downstream O2 sensors are not functioning normally. So any O2 sensor problems have to be dealt with before you can use the OBD II system to diagnose the converter. O2 sensors typically fail because of old age or contamination.
When does an O2 sensor set a trouble code?
If it’s not switching rapidly, the ECM will set an O2 sensor related trouble code If the upstream and downstream oxygens sensors are both switching from rich to lean, that’s the sign of a dead catalytic converter. An exhaust system leak really screws up the P0420 testing routing.