What year, model, make is your car? it could be anything from the computer to the wire coming from your wheel.
a fuse in the fuse box, look in the car manual for the position.
Because the car is not moving
There is a thing called a vehicle speed sensor on the car. If the car won't go over 20 mph then that is what it needs.
Need a new speedometer or speedometer cable.
what can cause the interior fan to stop waorking in a car is it stop working when your fuse blew
Anything that brings the car to a complete stop? Such as the brakes or a Tree?
Well due to the velocity of that car it could either be pressure building up in that part or a certain liquid is building up/leaking and it is creating technical difficulties such the speedometer to stop working
No.
Nope, bet it was the other way around... Your speedometer stopped working and your check engine light came on. A broken speedometer (don't know what car so I can't pinpoint it) will cause a whole bunch of codes.
Yes
alternater problem i found on my car
Yes, tires that are larger or smaller in diameter than original factory size will cause a car's speedometer to be wrong.