Wideband air/fuel ratio sensors utilize a sophisticated sensing element that enables them to measure the amount of oxygen in the exhaust rather than switching between rich and lean responses. Building on the planar sensor base, wideband sensors provide the ECU with an exact AFR response, resulting in better performance, lower emissions, and increased gas mileage. Planar sensors utilize the same zirconia ceramic sensing technology as their predecessor, the thimble sensor, but engineered into a more compact version. The heater and small sensing element are contained in the small, thin, flat tip of the sensor, enabling a smaller and lighter design that requires less power. The smaller design allows the sensor to be utilized in tighter, more compact areas. Wideband planar sensors utilize 5 or more wires.