Steering: Description and Operation

SYSTEM OUTLINE

PPS ECU (Flow rate control system) controls the solenoid valves mounted in the pump to conduct direct control of the pump flow rate in response to the vehicle speed possible, ensuring natural and real steering feeling.

1. PPS OPERATION
When the ignition SW is turned on, the starting current flows from the ECU-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.