Diesel Data: Automotive Repair

Speedometer Head: Description and Operation

SPEEDOMETER

The IPC displays the vehicle speed based on the information from the vehicle speed sensor. The PCM converts the data from the vehicle speed sensor to a 4000 pulses/mile signal. The IPC uses the vehicle speed signal circuit (4000 pulses/mile) from the PCM in order to calculate the vehicle speed. The speedometer defaults to 0 km/h (0 mph) if a malfunction in the vehicle speed signal circuit (4000 pulses/mile) exists. The speedometer displays either miles or kilometers as requested by the driver information center (DIC). The associated indicator km/h or MPH) illuminates.