p0420
Moderate
Nissan · Sedans
Catalyst System Efficiency Below Threshold Bank 1
Quick Answer
Error code P0420 on your Nissan Sedans means: Catalyst System Efficiency Below Threshold Bank 1. This is usually fixable — see the step-by-step guide below.
Affected Models
Applies to all models
Likely Causes
How to Fix It
1
Scan for related codes
2
Inspect catalytic converter for damage
3
Test oxygen sensors
4
Check for exhaust leaks
5
Perform back-pressure test
Pro Tip
This fix requires some technical knowledge. If you're unsure about any step, consider contacting support or a qualified technician.
Parts You May Need
Catalytic converter
Oxygen sensor
Exhaust gaskets
Secondary air pump
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