O2 Oxygen Sensor Upstream for Toyota Lexus US (1997-2003)

Precision Stoichiometric Control: Upstream Air/Fuel Ratio Sensor for 1MZ-FE & 3S-FE Powerplants

Who It’s For: Engineered for Toyota and Lexus owners running the legendary 1MZ-FE V6 or the 3S-FE inline-four who are dealing with California emissions requirements and a declining fuel economy. If your mid-size sedan or SUV is feeling sluggish, this is the first place you look.

The Symptom: The factory upstream sensors on the [1MZ-FE] and [3S-FE] are the "eyes" of your ECU. Over time, carbon buildup and heat cycles "poison" the sensor’s zirconia element, leading to slow response times. You’ll notice the engine struggling to find its idle, a noticeable hesitation during part-throttle acceleration, and a significant drop in MPG as the computer defaults to a "safe" rich fuel map to prevent lean-condition knock.

The Engineering Fix: This isn’t just a basic oxygen sensor; it’s a wideband-style Air/Fuel Ratio sensor designed for the upstream position. By utilizing a high-grade ceramic element and a double-laser-welded stainless steel body, this sensor provides high-speed feedback to the ECU. It allows for precise "Stoichiometric" (14.7:1) air-to-fuel ratio management, thinning out the fuel mixture during cruise while ensuring the engine gets the enrichment it needs the moment you step on the gas.

Why Mechanics Choose This Kit

• [Optimized Combustion]: Restores the factory-intended power curve by ensuring the ECU isn’t guessing at fuel trims.
• [Thermal Stability]: The 4-wire heated configuration reaches operating temperature in seconds, reducing "open-loop" run time where your engine is at its least efficient.
• [OEM-Spec Integration]: Features a 500mm lead with a correct grey-style connector for a true plug-and-play installation—no hack-job wiring required.

Technical Specifications

Compatibility & OEM Reference

Fits the Following Vehicles:

• 1997-1999 Lexus ES300 V6 3.0L (California Emissions)
• 1999-2003 Lexus RX300 V6 3.0L (California Emissions)
• 1997-1999 Toyota Avalon V6 3.0L (California Emissions)
• 1997-2000 Toyota Camry V6 3.0L (California Emissions)
• 2001-2003 Toyota Highlander V6 3.0L (California Emissions)
• 1997-2000 Toyota Rav4 L4 2.0L (California Emissions)
• 1999-2000 Toyota Sienna V6 3.0L (California Emissions)
• 1999-2000 Toyota Solara V6 3.0L (California Emissions)

Interchange Part Numbers:

234-9009, 89467-48011, 25697, SG1188, SG1197, SG1863, SG635, SG848, SG851, 8946741010, 8946741011

The Performance Promise

Buy with confidence. Don’t let a tired sensor kill your performance and fuel economy. These units are built to withstand the high-heat environment of the Toyota exhaust manifold while maintaining signal integrity. Backed by real automotive experts and fast shipping.