System Outline

The ECU of the PPS (Hydraulic reaction type) controls the hydraulic pressure applied to the hydraulic reaction chamber in the gear box control unit to change the steering force and provide optimum steering feeling at any vehicle speed and under any steering conditions.

PPS Operation 

When the ignition SW is turned on, the starting current flows from the ABS-IG fuse to TERMINAL 4 of the PPS ECU. The vehicle speed sensor monitors the vehicle speed and transmits control signals to TERMINAL 5 of the ECU.

When the vehicle speed is low, the PPS ECU sends a higher-current from TERMINAL 1 of the ECU to TERMINAL 1 of the PPS solenoid to TERMINAL 2 to TERMINAL 2 of the ECU to TERMINAL 6 to GROUND, increasing the solenoid valve opening angle to provide comfortable steering operation. When the vehicle speed is high, the PPS ECU decreases the solenoid valve opening angle by reducing the current to the valve to provide responsive steering feeling.