If your vehicle is showing speedometer reads zero while driving, here are the most likely causes and the parts you'll need to fix each one.
The sensor mounted on the transmission or transfer case that measures vehicle speed has failed, cutting off the signal to the speedometer.
Many modern vehicles calculate vehicle speed using the ABS wheel speed sensors. If a sensor fails, the speedometer may drop to zero and the ABS warning light will usually illuminate.
Often occurring after recent transmission, clutch, or engine work, the speed sensor electrical connector was accidentally left unplugged, pinched, or damaged during reassembly.
The small electric stepper motor behind the speedometer needle has burned out, or the instrument cluster's internal circuit board has failed.
In vehicles that route speed data through the anti-lock braking system, a catastrophic failure of the main ABS computer will cause a total loss of the speedometer signal.