How many oxygen sensors does a typical car have, and what factors determine this number? Additionally, how do their placements affect engine performance and emissions control? Thomas Hello Thomas, the ...

As the name suggests, oxygen sensors in a car’s exhaust system sniff for oxygen, the presence of which indicates incomplete combustion and unchecked pollution. This can trigger the check engine light.

QUESTION: I own a 1999 Buick Century. The indicator that shows gear position does not light up, and at night I cannot see what gear I am in. Is this an expensive repair and worth getting fixed? ANSWER ...

As snow, ice, or salt grime gathers on cars in winter, many of the sensors that are key to the operation of advanced safety systems can become blocked and shut down—right when you may need them most.