P0430 on Chevrolet: Catalyst System Efficiency Below Threshold (Bank 2)
Severity: 2 of 4
Usually drivable for a short time with a steady light and normal running. Plan a diagnosis soon. A flashing light, sulfur smell with power loss, or a red hot converter means park it.
Estimate range covers the repairs listed below; see the cost breakdown. A flashing check engine light, a hot temperature gauge, or brakes that feel different mean stop driving and get help.
What P0430 usually means on a Chevrolet
V6 and V8 Chevrolet trucks and SUVs often set P0430 alongside or instead of P0420. Lifter related misfires on cylinder deactivation engines can damage one bank's converter.
Most likely causes on Chevrolet vehicles
- Exhaust manifold leak
- Bank 2 rear oxygen sensor
- Misfire on bank 2
- Worn converter
Order reflects cost and likelihood in general; your vehicle may differ. Confirm with testing before buying parts.
Chevrolet specific tips
- Check for misfire codes on bank 2 cylinders.
Estimated repair cost
This is an estimate, built from typical parts price ranges plus labor hours times an assumed shop rate of $110 to $190 per hour. Actual prices vary by vehicle, region, and shop. Diagnosis fees are often extra.
| Repair | Parts | Labor | Estimate (low / high) |
|---|---|---|---|
| Rear oxygen sensor, bank 2 | $30 to $120 | 0.3 to 1.2 h | $30 + 0.3 × $110 = $63 $120 + 1.2 × $190 = $348 |
| Exhaust leak repair | $15 to $150 | 0.5 to 2.0 h | $15 + 0.5 × $110 = $70 $150 + 2.0 × $190 = $530 |
| Bank 2 catalytic converter (aftermarket) | $250 to $1,400 | 1.0 to 3.0 h | $250 + 1.0 × $110 = $360 $1,400 + 3.0 × $190 = $1,970 |
Costs are generic for this code; parts and labor on some Chevrolet models may run higher.
Watch a repair video
P0420 How To Diagnose A Bad Catalytic Converter (EricTheCarGuy); same test applies to bank 2. Third-party video, loads from YouTube (privacy-enhanced mode) only when you press play. Procedures vary by vehicle. Search YouTube for “P0430 Chevrolet fix” videos.
Repair manuals
Step-by-step service manuals for Chevrolet with torque specs and wiring diagrams:
Haynes manuals for Chevrolet Chilton manuals
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Check Chevrolet recalls
Enter your VIN at the NHTSA recall lookup before paying for repairs.
FAQ
Can I replace only one converter?
Yes if only one is failing, though many owners replace both at high mileage.
Read the full P0430 guide or more Chevrolet check engine notes.