Circuit Operation

The Two Flow Electronic (TFE) Steering system increases and decreases power steering assistance depending on vehicle speed. At speeds less than 20 mph power steering assistance is increased, while at speeds greater than 20 mph power steering assistance is decreased.

Power steering assistance is increased or decreased by the Multi-Function Chime Module (MFC) energizing or de-energizing the TFE solenoid. Whenever the ignition switch is ON and a Powertrain Control Module (PCM) conditioned Vehicle Speed Sensor (VSS) signal is received, which meets one of the following parameters:
^ Vehicle is increasing speed, and the speed is between 0 and 20 mph.
^ Vehicle is decreasing speed, and the speed is less than 17mph.

The MFC module grounds Terminal B8, energizing the TFE steering solenoid (power steering assistance increased). The VSS signal received by the MFC module is generated by the PCM.
NOTE: If no VSS signal is received within 120 seconds, vehicle is considered not moving and the MFC module opens switch and the TFE solenoid is de-energized (power steering assistance decreases).