P0420 and P0430 Codes on 2002 Toyota RAV4: How to Fix for Smog Check at Low Cost
I'm trying to pass a California smog check on my 2002 Toyota RAV4, but the check engine light is on due to both P0420 and P0430 diagnostic codes. While the vehicle passes emissions testing, I cannot get full approval without resolving these codes. The car has 207,000 miles and I'm looking for a cost-effective solution. A local repair shop suggested replacing the catalytic converters, oxygen sensors, spark plugs, and air/fuel ratio sensors for $1,800 — which seems excessive given the mileage. Since this is a high-mileage vehicle, my main goal is to pass smog check with minimal expense rather than long-term reliability. My question: Would it make sense to replace just the catalytic converters first and see if the codes clear? I'm concerned about replacing all components at once when only the cats might be faulty. Given that both P0420 and P0430 are present, I believe they may relate to the two catalytic converters in this model. I've had new spark plugs and ignition coil installed at 190,000 miles due to a previous P0300 code on cylinder #3. The oxygen sensors or air/fuel ratio sensors — if faulty — would likely trigger additional codes, so I'm hoping the issue is limited to the catalytic converters. Any advice on diagnosing and fixing this at low cost? Thanks in advance.
How long has it been since the last tune-up? With over 200,000 miles, worn-out catalytic converters are a common issue. It's unusual for both P0420 and P0430 to appear simultaneously — they typically correspond to left and right catalytic converters in this model. I'd recommend avoiding replacement of the air/fuel ratio sensors unless absolutely necessary. Focus on the cats first.