Wideband Oxygen Sensor (Air-fuel Ratio Sensor)
A wideband oxygen sensor measures the exact air-fuel ratio over a wide range, not just rich or lean.
What is Wideband Oxygen Sensor (Air-fuel Ratio Sensor)?
It is used before the catalytic converter on most modern engines. Diesel engines also use it. Its signal is often shown as lambda or current. Engine control units use it for precise mixture control, especially during warm-up and under load. Scan tools may display the value as lambda, equivalence ratio or milliamps depending on the system.
How it works
A pump cell and a control circuit keep a measuring cell balanced, and the pump current indicates the mixture.
Why it matters for your car
It needs the correct heater circuit to work. Its readings differ from narrowband sensors.
Other terms
- Battery Charger (Smart Charger)
- Boost Pressure Sensor
- Brake Fluid DOT Ratings
- Cell Balancing
- Dashboard (Dash Panel)
- Detonation (Engine Knock)
- Dipstick
- Door Handle
- DPF Warning Light
- Over-the-air Update (OTA)
- Paint Blistering (Rust Bubbles)
- Paintless Dent Repair (PDR)
- Peak Charging Power (Max kW)
- Primer (Primer Surfacer)
- Refractometer (Coolant And AdBlue Tester)
- Rinseless Wash
- Shift Interlock
- Vehicle History Report
- Water Pump
- Wheel Nut Torque