Oxygen sensor schematics are online at Britannica.com, Idronaut.it, Autozone.com, Dynancer.com and PicoAuto.com. Some, such as the one at Britannica.com, demonstrate how oxygen sensors work. Others, such as the one at Autozone.com, show how wiring is set up.
The Britannica oxygen sensor schematic is a three-dimensional representation of a generalized zirconia oxygen sensor. The Idronaut.it schematics are for a specific polarographic dissolved oxygen sensor. The Autozone.com oxygen sensor schematics come from a repair guide for 1994 through 2000 Acura coupes and sedans. Dynancer.com contains a schematic of a generalized oxygen level sensor. PicoAuto.com contains schematics of zirconia and titania lambda sensors.