Catalytic Converter for Lexus RX400h (2006-2008) 3.3L

Direct-Fit Catalytic Converter for 2006-2008 Lexus RX (MHU38)

What it Does: The catalytic converter replaces depleted or physically fractured emissions components on the 2006-2008 RX to resolve catalyst efficiency DTCs, silence substrate rattles, and restore factory exhaust flow.

The Stock Lexus RX Catalyst Washcoat Degradation

The factory catalytic converter on the MHU38 Lexus RX400h undergoes severe thermal cycling caused by frequent internal combustion engine start-stop sequences managed by the 3MZ-FE Hybrid Synergy Drive system. Over extended mileage, rapid heat fluctuation fractures the internal ceramic monolith or sinters the precious metal washcoat, degrading catalytic efficiency. This breakdown generates unmetered exhaust restriction, causes broken substrate blocks to rattle inside the shell under load, and triggers persistent downstream diagnostic trouble codes such as P0420 and P0430.

The Engineering Solution

Engineered as a bolt-on replacement, this direct-fit unit features a durable 409 stainless steel outer casing and precision TIG-welded tubing that resist thermal fatigue and corrosion. Inside, a high-flow ceramic honeycomb substrate coated with an active precious-metal washcoat rapidly catalyzes hydrocarbons, carbon monoxide, and oxides of nitrogen into harmless gases. Factory-positioned oxygen sensor bungs and heavy-gauge OE-style mating flanges ensure complete alignment with original hangers and downpipes without cutting, bending, or welding.

What's Included

• 1 x Direct-Fit Catalytic Converter
• Exhaust Gasket(s)
• Mounting Hardware

Technical Specifications

Compatibility

• 2006 Lexus RX400h Base 3.3L V6 Hybrid
• 2007 Lexus RX400h Base 3.3L V6 Hybrid
• 2008 Lexus RX400h Base 3.3L V6 Hybrid

Frequently Asked Questions & Fitment Warnings

Does this fit the MHU38 RX?

Yes, this is a direct fit for the 2006-2008 Lexus RX equipped with the 3MZ-FE 3.3L hybrid engine. Note: This EPA 49-state compliant unit is not legal for sale or operation on vehicles registered in California or CARB-adopting states.

Will this resolve active P0420/P0430 codes?

Yes, replacing an exhausted catalyst core with this fresh substrate restores conversion efficiency, stabilizing downstream O2 sensor voltage readings to eliminate diagnostic trouble codes.

The Lexus Refinement Standard

Preserve the smooth, silent operation and emissions compliance expected of your luxury hybrid platform without sacrificing engine performance or factory fitment tolerances.