Denso Oxygen Sensor 234-4168 — Direct-Fit 4‑Wire Heated O2 Sensor with 13.8in Harness for Lexus/Scion/Toyota

Denso 234-4168 is a direct-fit narrow-band oxygen (O2) sensor designed to replace the factory unit on select Lexus, Scion and Toyota vehicles for reliable emissions sensing and long service life.

This premium replacement sensor matches original-equipment specifications and includes a 13.78-inch four-wire harness for plug-and-play installation. Denso engineers the sensing element and protective layers to resist contaminants that shorten sensor life, helping maintain accurate air-fuel feedback for engine management systems. The 234-4168 fits specified model years for Lexus RX330, multiple Scion vehicles and several Toyota platforms, giving technicians and owners an OE-style option when a failing oxygen sensor triggers a check engine light or causes drivability concerns.

How will this O2 sensor affect my vehicle's engine performance?

Replacing a failing oxygen sensor with the Denso 234-4168 restores accurate exhaust-gas readings to the engine control unit (ECU), which helps the ECU trim fuel delivery correctly. That improved feedback lets the engine run closer to its intended air-fuel ratio, reducing rough idling and helping smooth acceleration.

• Precision sensing element for consistent voltage output
• Aluminum oxide trap layer protects against silicone and lead contamination
• Four-wire connector provides heated operation for faster response
• Direct-fit design avoids modification or splicing

Is the Denso 234-4168 simple to install, and what comes with it?

The sensor ships with an attached 13.78-inch wiring harness and four-pin connector so most installations are plug-and-play when replacing the corresponding OEM sensor. Installation requires basic hand tools and common safety precautions; some vehicles may require lifting the vehicle or removing heat shields for access.

• Included: sensor with pre-attached 13.78" (350 mm) four-wire harness
• Designed for first-time fit to the listed models—no extra parts needed
• Typical installation: unplug old sensor, remove, screw in new sensor, and reconnect harness
• Heated element shortens warm-up time for reliable closed-loop operation

Which cars and years does this Denso part number fit?

Denso 234-4168 is specified for a set of Lexus, Scion and Toyota vehicles where the original equipment used a narrow-band, four-wire heated sensor. Confirm fitment by comparing part numbers or checking vehicle application guides before purchase.

• Lexus RX330: 2004–2006
• Scion iQ: 2012–2015
• Scion xB: 2008–2015
• Toyota Highlander: 2004–2007; Sienna: 2004–2006; Venza: 2009–2014

What reliability features does Denso build into this oxygen sensor?

Denso manufactures sensors to tight OE tolerances and adds material protections to extend service life in harsh exhaust environments. The design focuses on resisting common poisoning agents while preserving rapid sensor response for accurate closed-loop operation.

• OE-quality construction and testing standards
• Aluminum oxide trap layer resists silicone and lead contamination
• Durable housing and wiring insulation for heat and vibration resistance
• Heater circuit supports quicker operation after cold starts

Who is this for: The Denso 234-4168 suits DIY mechanics, professional technicians and vehicle owners who need an OE-grade replacement oxygen sensor for the listed Lexus, Scion and Toyota models. It’s appropriate when a diagnostics scan identifies a failing narrow-band heated O2 sensor, or when symptoms such as inconsistent idle, reduced fuel economy, or an illuminated emissions-related fault code indicate sensor replacement. Always verify vehicle compatibility and OEM connector type before ordering to ensure correct fitment.