P0431: Warm up catalyst efficiency below threshold (Bank 2)
Drive carefully. Get it checked within a week or two.
Can I drive with P0431?
Yes, but drive carefully and get it checked soon. Bank 2 manifold catalyst is worn out; safe to drive until emissions inspection.
What does P0431 mean?
P0431 stands for Warm Up Catalyst Efficiency Below Threshold (Bank 2).
Symptoms you may notice
- Check engine light stays steadily illuminated
- little noticeable loss in driving power or throttle response
- Rotten egg / sulfur odor from tailpipe in some cases
- Automatic failure during state emissions inspection
How much does it cost to fix?
Repair costs for code P0431 depend on the specific underlying root cause, ranging from simple DIY checks to component replacement. The table below lists the most common causes and rough price ranges in USD:
- Worn Bank 2 warm-up catalyst
- Exhaust manifold gasket leak
- Failing oxygen sensor
- Engine oil burning into exhaust
What to do next
- Inspect Bank 2 manifold for exhaust soot.
- Verify O2 sensor voltage output.
- Replace Bank 2 manifold catalyst.
Last updated: October 2026
Related codes
General guidance only, not a professional diagnosis. If the check-engine light is flashing, or the car is running rough, overheating or losing power, stop driving and get help.
About this code
Code P0431 is the Bank 2 equivalent of P0421. The vehicle will drive without any performance degradation.