Catalytic Converter for Mazda B-Series B4000 (2007-2009) 4.0L Left & Right

Direct-Fit Left & Right Catalytic Converter Set for 2007-2009 Mazda B-Series,B4000 (UN Chassis)

What it Does: The Left & Right Catalytic Converter Set replaces degraded exhaust catalysts on the 2007-2009 Mazda B-Series B4000 to eliminate P0420/P0430 trouble codes and restore factory exhaust velocity.

The Stock Mazda B-Series,B4000 Catalyst Deterioration

Under repeated thermal cycling, heavy payloads, and towing strain, the factory exhaust catalyst on the UN chassis suffers washcoat depletion and thermal matrix degradation. Over time, internal ceramic blocks choke under sustained heat, leading to substrate micro-fractures, exhaust backpressure spikes, and recurring P0420 or P0430 diagnostic codes. Furthermore, aging factory flanges corrode, leading to pre-catalyst exhaust leaks that skew upstream oxygen sensor data.

The Engineering Solution

Built specifically for the 4.0L Cologne SOHC V6, this dual-bank direct replacement assembly utilizes high-grade stainless steel outer casings paired with heavy-duty ceramic honeycomb substrates. Formulated with a balanced noble-metal washcoat, it delivers rapid catalyst light-off and reliable emissions conversion. Precision-machined, mandrel-bent downpipes match factory routing, while thick mounting flanges and factory-positioned O2 sensor ports allow bolt-on fitment without cutting or custom fabrication.

Technical Specifications

Compatibility

• 2007 Mazda B-Series B4000 4.0L V6 Left & Right
• 2008 Mazda B-Series B4000 4.0L V6 Left & Right
• 2009 Mazda B-Series B4000 4.0L V6 Left & Right

Frequently Asked Questions

Does this fit the UN B-Series,B4000?

Yes, this is a direct fit for the 2007-2009 Mazda B-Series,B4000 equipped with the 4.0L Cologne SOHC V6 engine.

Is this catalytic converter legal for road use in California or New York?

No, this unit is 46-state EPA compliant and cannot be sold or registered in California, New York, Colorado, or Maine.

The Mazda Truck Durability Standard

Mid-size truck platforms require exhaust components capable of withstanding rough washboard trails, heavy towing loads, and off-road chassis flex. This converter assembly provides the structural resilience and high-temp corrosion resistance necessary for long-term utility.