A Guide to Replacing the Catalytic Converter on Your 2007-2020 Lexus RX350
Facing a check engine light with codes P0420 or P0430 on your RX350? This guide covers everything you need to know before you buy a new aftermarket catalytic converter.
- The RX350 has three catalytic converters; codes P0420 and P0430 point to the manifold converters (Bank 1 or Bank 2).
- Always diagnose and fix the root cause of the original failure (like bad O2 sensors or misfires) before installing a new converter.
- Lexus emissions systems are sensitive; cheaper aftermarket brands may not prevent the check engine light from returning.
- Check if your state requires a more expensive CARB-compliant converter before purchasing a Federal/EPA model.
Is Your Lexus RX350 Catalytic Converter Failing?
A failing catalytic converter can cause several noticeable problems. The most common sign is the check engine light appearing on your dashboard. If you use a code reader, you'll likely see codes P0420 (Catalyst System Efficiency Below Threshold Bank 1) or P0430 (Catalyst System Efficiency Below Threshold Bank 2). These codes mean the converter on either Bank 1 (firewall side) or Bank 2 (radiator side) is no longer working efficiently.
Other symptoms include:
- Reduced Acceleration and Power: A clogged converter restricts exhaust flow, making the engine feel sluggish.
- Rotten Egg Smell: A failing converter can't properly process sulfur in the gasoline, leading to a distinct sulfur or rotten egg smell from the exhaust.
- Rattling Noises: The internal honeycomb structure of the converter can break apart over time, causing a rattling sound from under the vehicle.
- Failed Emissions Test: This is a clear sign the converter is not cleaning the exhaust gases as required.
Always Diagnose First
Before you replace a catalytic converter, it's crucial to find out why the original one failed. A new converter can be quickly ruined by an underlying engine issue. Common causes of failure include faulty oxygen sensors, engine misfires from bad spark plugs, or oil and coolant leaks contaminating the exhaust. Always fix these related problems first.
🎬 Watch: A master mechanic's guide to performing a complete diagnosis.Choosing the Right Aftermarket Converter for Your RX350
When replacing a converter on your RX350, you'll choose between Original Equipment Manufacturer (OEM) and aftermarket parts. OEM parts from Lexus are extremely expensive but offer guaranteed fit and quality. Aftermarket parts are much more affordable, but quality and fit can vary significantly by brand. Lexus vehicles can be sensitive, and a low-quality aftermarket converter may not work well enough to keep the check engine light off.
Aftermarket Brand Tiers
Based on owner feedback and general reputation, aftermarket brands for the RX350 can be grouped into tiers:
- Premium Aftermarket (MagnaFlow, Walker): These brands are well-regarded for their quality and performance. MagnaFlow is often praised for its stainless steel construction and good flow, while Walker is known as a major OEM supplier with direct-fit designs that ease installation. They are more expensive but are a safer bet to avoid check engine light issues.
- Standard/Economy Aftermarket (AP Exhaust, Eastern Catalytic, Davico): These brands offer significant cost savings. However, experiences are mixed. Some owners report success with brands like Eastern Catalytic, noting good fitment. Others have experienced issues with poor welds, fitment problems requiring modification, and a higher chance of the check engine light returning. Davico, for example, is known for being budget-friendly, but users report hit-or-miss fitment and minimal heat shielding.
Federal vs. CARB Compliance
Always check your state's emissions requirements. If you live in California, New York, Colorado, or Maine, you must install a converter that is certified by the California Air Resources Board (CARB). Federal (EPA) converters are not legal in these states. CARB-compliant converters have higher loads of precious metals and are more expensive, but they are built to a higher standard.
How Many Converters Does the RX350 Have?
The 2007-2020 Lexus RX350 has three catalytic converters. Two are primary converters built into the exhaust manifolds—one for each bank of the V6 engine. Bank 1 is on the firewall side (rear), and Bank 2 is on the radiator side (front). The third converter is located downstream in the center exhaust pipe. The P0420 and P0430 codes almost always refer to one of the two manifold converters.
Cost to Replace a Lexus RX350 Catalytic Converter
Replacement costs vary based on the part you choose and local labor rates. The manifold converters are more labor-intensive to replace than the center one.
| Part/Service | Estimated Cost |
|---|---|
| New OEM Part | $1,800 - $3,000 |
| New Aftermarket Part | $133 - $1,134 |
| Shop Labor | $232 - $400 |
| Total Aftermarket Replacement | $365 - $1,534 |
Frequently Asked Questions
Will an aftermarket converter cause a check engine light on my Lexus?
It can. Lexus vehicles are known for having sensitive emissions systems. A cheap, low-quality aftermarket converter may not have enough precious metals to work efficiently, which can cause the P0420/P0430 codes to return. Choosing a higher-quality, direct-fit aftermarket brand like MagnaFlow or a CARB-compliant unit (even if not required by your state) can reduce this risk.
Which converter is Bank 1 and which is Bank 2?
On the Lexus RX350's V6 engine, Bank 1 (related to code P0420) is the cylinder bank closer to the firewall. Bank 2 (related to code P0430) is the cylinder bank closer to the radiator and is generally easier to access.
🎬 See this step-by-step walkthrough for replacing the Bank 2 converter.Are there any recalls for the RX350 catalytic converter?
There are no specific recalls for catalytic converter failure on the 2007-2020 RX350. However, Lexus did issue a Technical Service Bulletin (TSB L-SB-0003-23) for some 2016-2022 models for a droning noise from the exhaust system under light acceleration, which involves replacing the center exhaust pipe. TSBs are not recalls but are official repair procedures for known issues.
Is catalytic converter theft a problem for the Lexus RX350?
Yes, the Lexus RX350 is a known target for catalytic converter theft due to the value of the precious metals inside. To protect your vehicle, consider parking in well-lit areas or a garage, and think about having a catalytic converter shield installed by a muffler shop.
🎬 Watch: How a catalytic converter guard is installed for protection.Helpful Videos
Technical Specifications
OEM Part Numbers: 17420-0P250 17420-31570 17420-0P540
The 2007-2020 Lexus RX350 uses a V6 engine with three catalytic converters. Two are manifold-style converters (Bank 1/Firewall Side and Bank 2/Radiator Side) and one is a center/downstream converter. Replacements are available as direct-fit bolt-on units or universal-fit weld-in units. Direct-fit is strongly recommended for easier installation and better performance on this vehicle.
We Have This Part in Stock
The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
- Lexus RX350: