P0430 Nissan Altima
Catalyst System Efficiency Below Threshold (Bank 2) · Powertrain Code · Medium
What is P0430?
The catalytic converter on bank 2 is not operating efficiently. Same as P0420 but for the opposite bank.
When the Nissan Altima triggers code P0430 (catalyst system efficiency below threshold (bank 2)), it typically points to an issue in the powertrain system. Below you'll find the most common causes, symptoms, and repair options specific to the Nissan Altima.
Diagnostic data on this page is compiled from publicly available repair resources and technical service bulletins. Always have a qualified mechanic confirm the diagnosis before authorizing repairs on your Nissan Altima.
Common Causes on Nissan Altima
- Deteriorated catalytic converter on Bank 2 (VQ35 engines)
- Failed downstream O2 sensor giving false efficiency reading
- Misfire damage to the Bank 2 catalytic converter
- Exhaust leak near the Bank 2 converter
Symptoms
- Check Engine Light on
- Reduced power on acceleration
- Sulfur smell from exhaust
- Failed emissions test
Notes for Nissan Altima
P0430 is Bank 2 only, applies to VQ35 V6 models; Pathfinder and Altima 3.5 are most commonly affected.