The wide band lambda sensor LSU is a planar ZrO2dual cell limiting current sensor with an integrated heater. It is used to measure the oxygen content and the λ-value of exhaust gases in automotive engines (gasoline and diesel). Its monotonic output signal in the range of λ=0.7 to air makes the LSU capable of being used as an universal sensor for λ=1 measurement as well as for other λranges.