Q: What does a vehicle speed sensor look like?

There may be a couple of things going on at the same time here. Is the Check Engine Light on? A vehicle speed sensor problem may illuminate the Check Engine Light if the lack of signal is causing shifting errors. A vehicle speed sensor can be a 2 or 3 wires sensor and is usually mounted near a rotating object like a wheel bearing or on the extension housing of the transmission. A technician with the proper equipment can hook up to the car and observe the data being offered to the engine control computer and determine where the issues are. A lack of signal may cause shifting errors if the vehicle depends on speed to determine when to shift. A no start may come from loss of fuel pressure from a failed fuel pump or no spark due to lack of maintenance of spark plugs or the engine control computer failing to send spark. Consider hiring an experienced technician like one from YourMechanic who can come out and asses the problem to offer a more personal diagnosis.