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P0430: Catalyst System Efficiency Below Threshold (Bank 2)
Same as P0420 but on the other engine bank.
Medium Severity
$150 – $2,500
Can I Keep Driving with Code P0430?
Yes, but address it before the catalytic converter fails completely.
What P0430 Means
P0430 is the bank 2 version of P0420. On a V6 or V8 you have two catalytic converters, one per bank. Same diagnostic path applies.
Common Causes
- Failing catalytic converter on bank 2 — see repair cost
- Bad downstream O2 sensor — see repair cost
- Exhaust leak ahead of the rear sensor
Diagnostic Tips
- Confirm O2 sensors are good before replacing the cat.
- If both P0420 and P0430 are present, look upstream at causes like engine misfires.
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Get My Free EstimateFrequently Asked Questions
Do I have to replace both cats together?
Only if both are bad. Sometimes only one bank fails.