Denso 234-4778 Oxygen Sensor - Downstream

Denso OE Style Oxygen Sensor 234-4778

Denso 234-4778 is an OE Style heated oxygen sensor built for direct replacement in specific Nissan applications. It is engineered for exact fitment and stable signal performance, with a threaded mounting design and a 4-wire male connector for the listed downstream locations.

Key Features

• Heated oxygen sensor for downstream exhaust monitoring
• Specific fit design for direct replacement
• 4-wire configuration with male connector
• Threaded mounting type with 0.708 in. thread diameter
• 11.42 in. wiring harness length
• OE Style construction for Nissan Altima and Sentra applications

OE Style Design

Denso’s OE Style line is built to match original equipment fit and function for the listed vehicles. The sensor uses precision-built components for first-time fitment and includes Denso’s aluminum oxide trap layer, which helps protect the ceramic element from silicone and lead contamination. That design supports consistent exhaust feedback, fuel control, and long service life in normal operating conditions.

This part cross-references Bosch 15963 and NTK 24638 for the same application.

Vehicle Fitment

• Fits 2002 Nissan Sentra, downstream; Clean Air Vehicle; OE Style
• Fits 2001 Nissan Altima, downstream; To 12/00; OE Style
• Fits 2000-2001 Nissan Sentra, downstream; OE Style
• Fits 2000-2001 Nissan Sentra, downstream; Clean Air Vehicle, Located After Underfloor Catalyst; OE Style
• Fits 2000 Nissan Altima, downstream; OE Style

What It Helps Address

• Check engine light related to downstream oxygen sensor faults
• Incorrect air-fuel feedback from a worn sensor
• Reduced fuel economy caused by inaccurate exhaust readings
• Slow sensor response after catalyst monitoring issues
• Replacement needs for damaged or contaminated OE-style sensors

Installation Notes

Verify the connector style, wire count, thread diameter, and downstream location before installation. This sensor is specific fit, so match the vehicle build date and emissions notes exactly, especially for 2001 Altima models listed as “To 12/00” and 2000-2001 Sentra Clean Air Vehicle applications. Inspect the exhaust bung threads and wiring routing before tightening the sensor into place.

Quality Assurance

Denso manufactures and tests this oxygen sensor to OE standards for fit and performance. The part number 234-4778 is built as a direct replacement for the listed Nissan applications, with attention to sensor durability and consistent operation.