Catalytic Converter for Jaguar XJ8 (2004-2009) 4.2L Left & Right

Direct-Fit EPA Catalytic Converter Pair for 2004-2009 Jaguar XJ8 (X350)

What it Does: The direct-fit catalytic converter pair replaces degraded factory emissions assemblies on the 2004-2009 Jaguar XJ8 to clear catalytic efficiency error codes, eliminate internal substrate rattle, and restore proper exhaust gas scavenging.

The Stock Jaguar XJ8 Substrate Degradation

As mileage accumulates on the X350 chassis, sustained thermal cycles and continuous exhaust gas temperatures deteriorate the internal ceramic washcoat inside the factory converters. On the naturally aspirated AJ34 4.2L V8, aged cores succumb to chemical poisoning and physical matrix fracturing. This triggers downstream oxygen sensor faults—specifically DTC codes P0420 and P0430—while loose, broken monolith fragments create distinct metallic rattles and generate unwanted exhaust backpressure that hampers high-RPM efficiency.

The Engineering Solution

Engineered for a direct bolt-on installation, this left and right catalytic converter set features robust stainless steel tubing and OE-style mating flanges that seal directly to factory mounting locations. Within the corrosion-resistant steel bodies, dense ceramic honeycomb monoliths coated in precious-metal catalysts (platinum, palladium, and rhodium) maximize the conversion of HC, CO, and NOx into compliant emissions. Integrated sensor bungs maintain proper downstream O2 sensor orientation to restore factory air-fuel feedback loops without cutting, bending, or welding.

What's Included

• 1 x Left-Side Direct-Fit Catalytic Converter
• 1 x Right-Side Direct-Fit Catalytic Converter
• Exhaust Flange Gaskets
• Mounting Hardware

Technical Specifications

Compatibility

• 2004 Jaguar XJ8 4.2L V8 (Left & Right)
• 2005 Jaguar XJ8 4.2L V8 (Left & Right)
• 2006 Jaguar XJ8 4.2L V8 (Left & Right)
• 2007 Jaguar XJ8 4.2L V8 (Left & Right)
• 2008 Jaguar XJ8 4.2L V8 (Left & Right)
• 2009 Jaguar XJ8 4.2L V8 (Left & Right)

Frequently Asked Questions & Fitment Warnings

Does this fit the X350 XJ8?

Yes, this is a direct fit for the 2004-2009 Jaguar XJ8 equipped with the AJ34 4.2L engine. This 49-state EPA compliant unit is not CARB-approved and cannot be legally installed or registered in California or other CARB-adopting states.

Will this unit clear check engine codes P0420 and P0430?

Assuming your O2 sensors, exhaust manifold gaskets, and fuel trims are functioning correctly, replacing failed converters with this fresh catalyst matrix restores conversion efficiency to clear P0420 and P0430 fault codes.

The Jaguar Precision Standard

Preserve your European luxury sedan’s factory refinement with hardware engineered for precision acoustic balance, reliable emissions compliance, and permanent elimination of catalyst-related check engine lights.