P0423
Heated Catalyst Efficiency Below Threshold Bank 1
Generic code
Auxiliary Emissions Control
Medium severity
Moderate repair
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What P0423 means
- The fault code P0423 indicates that the efficiency of the heated catalyst is below the threshold for Bank 1.
Possible symptoms
- Illuminated check engine light
- Failed emissions testing
- Reduced engine power or acceleration
- Rattling noise coming from the catalytic converter
Possible causes
- Failed catalytic converter
- Engine misfire or running too rich
- Faulty oxygen sensor(s)
- Exhaust leaks before or after the catalytic converter
Related parts
- Catalytic Converter: A catalytic converter is a device that converts toxic gases and pollutants to less harmful pollutants. Problems lead to harmful emissions out of limit, rotten egg smell from exhaust & reduced speed
Possible solutions
- Replace the catalytic converter
- Fix any underlying engine issues causing the catalyst system to fail
- Replace faulty oxygen sensor(s)
- Repair any exhaust leaks before or after the catalytic converter
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P0423 on OBD DashX
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