Circuit Description

Vehicle speed is signaled to PCM by Vehicle Speed Sensor (VSS). Sensor is a Permanent Magnet (PM) generator mounted to transmission case extension. PM generator produces an 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 and TCC apply and release. DTC P0502 is set if PCM detects a low vehicle output speed when vehicle has high engine speed in drive range.