ErrorStreet.com
P0420 Code Repair Cost
The cost to fix a P0420 code can vary widely, from under $100 to over $2,000. Here's what to expect.
Repair Cost Breakdown
The final cost depends entirely on what the actual cause is. This is why a proper diagnosis is critical before replacing parts. For more specific estimates, you can consult third-party resources like RepairPal or use our own cost estimator tool.
| Repair | DIY Cost (Parts) | Mechanic Cost (Total) | Notes |
|---|---|---|---|
| Catalytic Converter Cleaner | $15 - $30 | $100 - $150 | A low-cost first step. May not work if the converter is physically damaged. |
| Oxygen (O2) Sensor Replacement | $50 - $150 | $200 - $400 | A very common repair. Ensure you replace the correct sensor (downstream/Bank 1). |
| Exhaust Leak Repair | $20 - $100 (for sealant/clamps) | $150 - $500+ | Cost varies greatly depending on the location and whether welding is required. |
| Catalytic Converter Replacement | $200 - $800+ (Aftermarket) | $800 - $2,500+ | The most expensive fix. OEM parts cost more but are often more reliable. Prices in states like California (CARB-compliant) are significantly higher. |