Circuit Description

The vehicle speed sensor (VSS) provides vehicle speed information to the powertrain control module (PCM). The VSS is a permanent magnet generator. The VSS produces an AC voltage as rotor teeth on the output shaft of the transmission, 2WD, or transfer case, 4WD, pass through the sensor's magnetic field. The AC voltage level and the number of pulses increase as the speed of the vehicle increases. The PCM converts the pulsing voltage to vehicle speed. The PCM uses the vehicle speed signal to determine shift timing and torque converter clutch (TCC) scheduling.

When the PCM detects an unrealistically large drop in vehicle speed, then DTC P0503 sets. DTC P0503 is a type B DTC.