Circuit Description

Vehicle Speed Sensor (VSS) is a hall effect type sensor that interacts with magnetic field created by a rotating magnet attached to and rotated by transmission output shaft. Meter fuse supplies 12 volts to VSS hall sender circuit. VSS pulses a 9-volt signal sent on reference circuit from PCM to ground. PCM interprets vehicle speed by monitoring number of pulses to ground on reference circuit.

When DTC sets, PCM illuminates MIL on second trip after fault was detected. Vehicle operates in base shift logic on RPM only. PCM will store conditions present when DTC was set as freeze frame data in the FAILURE RECORDS data.

PCM will turn MIL off on third consecutive trip cycle during which diagnostic runs and fault is no longer recognized. A history DTC will clear after 40 consecutive trip cycles during which diagnostic runs and fault is no longer recognized. DTC can be cleared with scan tool, or by disconnecting battery voltage feed to PCM.