p0430
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BMW · SUVs
Catalyst System Efficiency Below Threshold Bank 2
Quick Answer
Error code P0430 on your BMW SUVs means: Catalyst System Efficiency Below Threshold Bank 2. This is usually fixable — see the step-by-step guide below.
Affected Models
Likely Causes
  1. Failed catalytic converter on bank 2
  2. Faulty downstream oxygen sensor on bank 2
  3. Exhaust leak near the bank 2 catalytic converter
  4. Prolonged rich or lean running condition damaging bank 2 catalyst
  5. Contaminated catalyst from coolant or oil leak
How to Fix It
1
Check for additional trouble codes affecting bank 2 fuel delivery
2
Monitor bank 2 downstream O2 sensor switching rate and amplitude
3
Inspect bank 2 exhaust components for leaks
4
Measure temperature differential across the bank 2 catalytic converter
5
Replace the bank 2 catalytic converter and downstream O2 sensor if needed
Pro Tip
This issue typically requires professional diagnosis. Attempting this fix without proper training could cause further problems.
Parts You May Need
Catalytic converter (bank 2)
Downstream oxygen sensor (bank 2)
Exhaust gaskets
Exhaust mounting hardware
Related Error Codes
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