P0430 — Catalyst System Efficiency Below Threshold (Bank 2)

P0430 is the Bank 2 sibling of P0420 — your catalytic converter on the side of the engine opposite cylinder 1 is failing to clean exhaust gases. Causes and fixes are identical to P0420.

Cost range: $200–$2,500. Severity: medium. Safe to drive? Yes for short-term driving, but you'll fail emissions and risk further damage.

Most common causes of P0430

1. Failing Bank 2 catalytic converter — Same wear pattern as P0420 but on the opposite cylinder bank. ($800–$2,500)
2. Faulty Bank 2 downstream O2 sensor — Sensor 2 on Bank 2 reports cat efficiency. ($150–$400)
3. Exhaust leak on Bank 2 — Pre-cat leak causes false lean reading. ($100–$500)

Symptoms drivers report with P0430

• Check engine light
• Failed emissions
• Reduced MPG