Knock Sensor and Speed Sensor on a Nissan Altima 95?

Question

I have a circuit Malfunction in my knock sensor, and just a malfunction in my speed sensor. What does circuit Malfunction mean? any ideas of what the cost to fix this would be, or could I do it myself and if so what needs to be done, I know a new one will cost 150$, I also wondered about the steps to change the speed sensor, which for a new one is about 112$, any ideas to change one or both of these ? or how much it would cost to get it fixed at a shop? thanks

also could you tell me what could go bad If I do not replace/fix the knock sensor.....
thanks

Answer 1

Just use name brand regular Gasoline and lack of knock sensor won't mean a thing. Knock sensor does not turn on the check engine light and is located under the intake manifold in the middle of the engine block. Speed sensor is a different matter there are two one at the transmission that sends an analoge signal to the spedometer head there that signal is digitized speed sensor #2 on off on off to the transmission control module and engine control module. That problem might not even affect the way the car drives. If the Trans. Controls do not get the right speed signal. The transmission will work in fail safe and start out in second gear and accelerate very slowly. If your car is starting out in second gear. You need to get a correct Nissan Diagnosis and repair. AND have you been new car shopping lately?