Air‑Fuel Ratio Sensor (Wideband O2) for precise mixture control ⚙️

This upstream A/F sensor keeps your engine at the ideal 14.7:1 air‑fuel mix so you get strong power, clean emissions, and better MPG. The ECU reads its signal and trims the injectors in closed loop. Replacing a tired unit restores smooth idle, crisp throttle, and protects the catalytic converter. A correct air fuel ratio sensor helps pass emissions and maintains reliability on and off road.

How it works

Inside is a planar zirconia element with a reference chamber and a tiny pump cell. A fast heater brings it to operating temperature, then the ECU drives pump current to hold stoichiometric oxygen. That current is translated into an exact lambda value across rich and lean. This wideband oxygen sensor is far more precise than a narrowband unit, delivering stable feedback for clean combustion and optimal fuel economy.

When it fails

Age, contamination, or a failed heater cause slow response or false readings. Symptoms: CEL, rough idle, poor MPG, hesitant acceleration, or failed emissions. Common codes: P2195/P2196, P0031/P0032. Driving with a bad A/F sensor can overfuel, foul plugs, dilute oil, and overheat the catalyst—risking costly damage. Replace promptly for restored performance and lower emissions.

Compatibility

• 4Runner
• Fj Cruiser
• Land Cruiser
• Land Cruiser Prado