Toyota code
P0420: on a Toyota
How much to fix P0420 on a Toyota? Typically $430 to $2,325 for catalytic converter replacement, the most common fix. This is an estimate, not a quote.
Toyota converters last a long time, so P0420 on one often points to something else upstream first: oil use, a leaking exhaust joint or an aging sensor. Check those before paying for a converter.
General meaning of P0420: The computer compares the oxygen sensor before the catalytic converter with the one after it. On this code the two readings look too alike, which suggests the converter is not cleaning the exhaust as well as it should on the side with cylinder 1. See the full P0420 page.
Models to know about
| Model | Years | What to know |
|---|---|---|
| Camry | 2007 to 2011 | The 2.4 four-cylinder in these years is known for oil use. |
| Corolla | 2009 to 2019 | Usually the rear sensor. |
| Prius | 2004 to 2015 | Hybrids run the converter cold, which changes the fault patterns. |
| Tacoma | 2005 to 2015 | Two converters on the V6. |
Common causes on a Toyota
- Rear oxygen sensor aging past 100,000 miles.
- Oil burning on the 2.4 that clogs the catalyst.
- Leaking exhaust gasket or flex pipe.
- Failing converter on Prius, where the engine often runs short and cold.
NHTSA's public complaint file shows how owners describe this kind of trouble: the 2009 Toyota Camry has 1,413 complaints on file, and 253 of them use wording like catalytic, check engine, P0420, oil; the 2010 Toyota Prius has 2,823 complaints on file, and 131 of them use wording like catalytic, check engine, P0420, oil. Complaints are owner reports, not proof of a cause.
Check this first
- Smell for oil in the exhaust and check the dipstick.
- Ask for a live-data check of the rear sensor, which should be steady, not mirroring the front.
- Inspect the exhaust joints for black soot.
Wide range: this job varies a lot. Itemize your quote for a better answer.
How this range is built
| Part of the job | Low | High |
|---|---|---|
| Parts | $300 | $1,900 |
| Labor: 1.2 to 2.5 hours × $110 to $150 an hour | $132 | $375 |
| Fees: shop supplies, disposal, diagnostics | $0 | $40 |
| Total, rounded | $430 | $2,325 |
The hourly rate is the BLS Occupational Employment and Wage Statistics, May 2025 average pay for this trade in the US, $27.13 an hour, times 4 to 5.5 to cover what a shop bills (overhead, tools, insurance, profit). Parts are a band from budget aftermarket to the manufacturer part. In California and New York, parts cost more because those states require a California-certified converter. Full method.
Not a repair shop, estimates only. Typical range, estimate. Not a quote. Your car, parts and shop change the number.
Toyota OEM converters cost the most of any brand in this list. The universal-fit option is cheaper but may not be legal in states that follow California rules.
Other repairs that may be involved
| Repair | Typical range, US |
|---|---|
| Catalytic converter replacement | $430 to $2,325 |
| Oxygen sensor replacement (one sensor) | $100 to $350 |
Questions to ask the shop
- Are you replacing the sensor first?
- Is the car burning oil?
- Is the new converter CARB-legal?
Got a quote already? Check it against the range. Wondering if a recall touches this problem? See Toyota recalls by model or check a VIN.
P0420 on a Toyota: questions
Is there an emissions warranty?
Possibly. Federal rules cover some parts up to 8 years or 80,000 miles. Ask a dealer to check.
Can I clear it for an inspection?
Not reliably. The monitors must finish again before an inspection.
How much does it cost to fix P0420 on a Toyota?
The most common fix, catalytic converter replacement, has a typical range of $430 to $2,325 across the US. That is an estimate built from parts prices and local labor wages, not a quote. Your model, engine and shop move it.
P0420 on other makes
Sources
- NHTSA complaints, 2009 Toyota Camry
- NHTSA complaints, 2010 Toyota Prius
- NHTSA recall lookup by VIN
- US federal emissions defect warranty rules (40 CFR part 85, subpart V)
Written from public NHTSA data, owner-reported patterns and general repair knowledge, in our own words. Model lists are examples, not a full list, and patterns are not a diagnosis. Prices updated October 2026. Not a repair shop, estimates only.