Speedometer Head: Description and Operation

Speedometer Circuit Operation
The Vehicle Speed Sensor (X190) sends a signal to the speedometer in the form of voltage pulses. The pulses are filtered by a Vehicle Speed Sensor Buffer inside the speedometer. The voltage alternates between battery voltage and 0 volts 6 times per wheel revolution. The speed sensor signal is also sent to the Cruise Control ECU (Z121). Multifunction Unit (MFU) (Z148) (Persian Gulf States). and the Engine Control Module (Z132).