Normal Operation
WARNING: This page is about a different car, the 2005 Mercury Mountaineer and 2005 Ford Explorer. However, it is still accessible from the selected car via links, so may be relevant.
The vehicle speed information is sent to the instrument cluster by the powertrain control module (PCM) over the communication network. If the instrument cluster fails to receive the speed input data from the PCM, the instrument cluster will not indicate any speed on the speedometer.