Contact your local calibration service station to have your vehicle calibrated for speed. To find one, contact your local police department because most police departments have their police cars calibrated. All else fails, take it to the nearest Toyota dealer!

speedometers run a inductive pulse generator to send a signal at varying frequency to your cluster to make to needle move up and down with speed. Seeing as how the needle recieves a current, at VARYING voltage to display the speed, i would suspect a short to earth in the speedometer transducer circuit. in other words, take it to a dealer!

I recommend changing the speedometer. You can buy a used one in working condition at ebay. If the speedometer is erroneous while car is moving, the speed sensor maybe broken. Another reason may be the ECM.

Take your corolla to a toyota dealer. tampering with an automobiles speedometer is a federal violation. if you have the proper papers, on the car, the toyota dealer can repair your speedometer. one has to wonder how your speedometer became so dysfunctional?