p0430
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Chevrolet · SUVs
Catalyst System Efficiency Below Threshold Bank 2
Quick Answer
Error code P0430 on your Chevrolet 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. Malfunctioning downstream O2 sensor (bank 2 sensor 2)
  3. Persistent engine misfire causing catalyst degradation
  4. Oil or coolant contamination of the catalyst substrate
  5. Exhaust leak before or at the bank 2 catalytic converter
How to Fix It
1
Scan for related codes and check freeze frame data for operating conditions
2
Monitor bank 2 upstream and downstream O2 sensor signals at steady cruise
3
Check for exhaust leaks around the bank 2 converter
4
Use an infrared thermometer to compare converter inlet and outlet temperatures
5
Replace the bank 2 catalytic converter if efficiency is confirmed low
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 O2 sensor (bank 2 sensor 2)
Exhaust gaskets and clamps
Related Error Codes
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