Air Fuel ratio sensor LSU 4.9 sensor interfacing ( oxygen sensor )

Thread Starter

Ali Raza_1441110966

Joined Sep 1, 2015
air fuel ratio sensor used in cars, model LSU 4.9 boash , controller Chip CJ125 , i have searched alot, lots of info is also available but till now i am not able to understand its basic working principle of this sensor, because i want to use this sensor without the Controller chip, i want 0 to 5 volt output but CJ125 gives data in SPI format.
also i am confused in functions of different pin out of this sensor.

Kindly help


Joined Sep 30, 2009
Google is your friend.


Joined Apr 28, 2013
Why are you building one when you can buy a cheap china made one for next to nothing or spend the money and get autometer gauges.


Joined Sep 1, 2012
wide-band O2 sensors are not that trivial - you need an external controller with a processor to control it and decode the output. Cheap controllers start at about $50, those would provide you with analog 0-5 signal you are looking for.