P0420 on a Toyota RAV4
P0420 means catalyst System Efficiency Below Threshold (Bank 1). On the RAV4, a few causes come up far more than others.
What P0420 usually means on a RAV4
On the RAV4, P0420 is a bank 1 catalyst-efficiency code that shows up mostly on higher-mileage four-cylinders as the factory converter tires out. The downstream oxygen sensor stops seeing the exhaust get cleaned up and the ECU flags the cat. It's a gradual, mileage-driven code, not a sudden breakdown, and the RAV4's steady highway use tends to bring it on around the six-figure mark. The check-engine light stays on with no real change in how the crossover drives.
Most common causes on the RAV4
- Aged original catalytic converter
The 2AR-FE RAV4 commonly reaches high mileage on its first cat, and efficiency simply declines.
- Slow downstream O2 sensor
A tired Denso rear sensor can mimic a failing cat, so confirm the sensor before replacing the converter.
- 2AZ-FE oil consumption
The 2006-2008 four can burn oil that fouls the catalyst substrate and shortens its life.
- Exhaust leak ahead of the cat
A rusted flex pipe or manifold gasket admits air and skews the reading on older RAV4s.
- Lingering misfire or lean run
Raw fuel from a weak coil or lean condition overheats the cat; clear those faults first.
What P0420 costs to fix on a RAV4
A direct-fit converter for a four-cylinder RAV4 runs a few hundred dollars in parts and installs quickly since the cat is accessible under the vehicle. The 2GR-FE V6 raises the cost because it uses two converters. Always test the rear O2 sensor and check for exhaust leaks first, so you don't buy a cat the RAV4 doesn't need.
Year, engine and mileage change the answer. Start a case and Redline weighs these causes against what your car shows, then names the check that would settle it.
RAV4 owners also ask
Does P0420 mean I need a new catalytic converter right away?
Not necessarily — a lazy rear O2 sensor or an exhaust leak can set it too. On a high-mileage RAV4 with the original cat, the converter is the likely cause, but have it confirmed before spending on one.
Will my RAV4 pass emissions with P0420 set?
No — the catalyst monitor reads failed or not-ready, which is an automatic emissions failure in most states. The RAV4 drives normally, but you'll need it fixed to renew registration.
Other codes on the Toyota RAV4
Related symptoms
Toyota RAV4 problems & recalls by year
Based on widely reported patterns for this model; individual causes vary by year, engine and history. Generic P0420 behavior is covered on the main P0420 page. Confirm with a scan tool before buying parts.
P0420 on your RAV4?
Every problem becomes a Case. Tell Redline what your RAV4 is doing: it shows what the evidence supports, what’s still missing, and what to check next, before you approve a repair.
“Inner pad ~1 mm. Outer pad 3 mm.”
Next: check the slide pins move freely before buying parts.