Where is the vehicle speed sensor located on a 1991 Honda Civic DX 1.5L?

On a 1991 Honda Civic DX 1.5L, the vehicle speed sensor (VSS) is typically located on the transmission. More specifically, it's usually mounted on the top or side of the transmission case, near where the speedometer cable would be on older vehicles (though this car uses an electronic system).

You'll likely need to get under the car to see it. It's a small sensor with a single wire connector. A repair manual specific to your year and model will provide the most accurate location and a diagram. Consult a trustworthy online parts store that allows you to select your specific vehicle year, make, and model; their diagrams often pinpoint the sensor's location.