Intermediate Shaft Speed Sensor
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 intermediate shaft speed sensor is a magnetic pickup that sends planetary sun gear speed information to the PCM. It is mounted externally on the center of the case.
The PCM uses the intermediate shaft speed sensor information to aid in determining pressure requirements.