DENSO 234-5170 Air/Fuel Ratio Sensor Direct Fit Heated Wire - 4-Wire 23.7

The DENSO 234-5170 is a 4-wire, direct-fit, heated air/fuel ratio (AFR) sensor with a 23.7-inch wire length. Also known as an AF sensor, AFR sensor, wideband oxygen sensor, or O2 sensor, this OE-style replacement is engineered to restore precise air-to-fuel mixture monitoring and protect your vehicle's emissions system performance.

Air/fuel ratio sensors are wide-band oxygen sensors designed to measure air-to-fuel ratios across a wider range of driving conditions than conventional oxygen sensors. The sensor continuously monitors exhaust gases and transmits data to the engine control unit (ECU), which uses this information to optimize fuel delivery, improve combustion efficiency, and reduce harmful emissions. A failing AFR sensor can cause poor fuel economy, increased emissions, and reduced engine performance.

Key Features:

• 4-Wire, Heated Design — Built-in heater element brings the sensor to operating temperature faster for quicker response, especially during cold starts
• Direct Fit — Precision-built for exact OE replacement with a first-time fit; no modifications required
• 23.7-Inch Wire Length — OE-matched harness length for a clean, factory-correct installation
• Tarnish-Proof Platinum Electrode — Provides longer service life while maintaining measurement accuracy over time
• Planar Zirconia Sensing Element — Delivers quick oxygen concentration detection and measures air/fuel ratios from approximately 12:1 to 19:1
• Double Protection Cover — Maintains proper sensor temperature for faster response and shields the ceramic element against silicone and lead contamination
• Aluminum-Oxide Trap Layer — Protects the platinum electrode and ceramic element from silicone and lead poisoning
• Stainless Steel Housing — Corrosion-resistant construction with a rugged, watertight body for long-term durability
• OE O-Rings and Thread Oil Included — Original equipment-specified hardware included for a complete, ready-to-install replacement

Manufactured and tested to the strictest OE standards, the DENSO 234-5170 is part of the DENSO First Time Fit® aftermarket program — the same engineering and quality processes DENSO uses as an original equipment supplier to vehicle manufacturers. Cross-references include OEM part numbers 68146231AB and 68171190AA, as well as NTK 27045, NTK 27084, Bosch 17213, and Walker Products 250-25108.