Circuit Description

Vehicle speed is signaled to PCM by Vehicle Speed Sensor (VSS). Sensor is a Permanent Magnet (PM) generator mounted to transaxle case extension. PM generator produces AC voltage as speed sensor rotor teeth pass sensor's magnetic field. PCM converts AC voltage into a digital signal. PCM uses vehicle speed to determine shift timing, torque converter clutch apply and release, and gear ratio calculations. VSS voltage will vary from .5 volt AC at 100 RPM to more than 200 volts AC at 6000 RPM. VSS resistance value is 981-1864 ohms. DTC P0502 will set if PCM detects a low vehicle speed when vehicle has high engine speed in Drive.