Review on Denso 234 9056 Fuel Ratio Sensor by Antonio Fox

One of the diagnostic findings on my newly purchased 2008 Prius was that the air/fuel ratio sensor was not giving the correct reading for the engine. Around the same time I read somewhere that this sensor (sometimes) didn't work properly when bought from an aftermarket supplier. It was specific and vague enough that I decided to try one of those aftermarket sensors. Paid for installation and then had to buy a proper Denso unit AND pay to have a Denso unit installed to fix problems caused by a (cheaper) aftermarket unit. All sensor related issues went away when the Denso unit was installed and my car is now out of the California smog and is my daily driver (with 215,000 miles).