HYDRAULIC PUMP ELECTRIC POWER STEERING SYSTEM: System Description
- The system is composed primarily of the power steering oil pump assembly (power steering control module, power steering motor, power steering oil pump, and reservoir tank), hydraulic pipes, and steering gear assembly.
- The power steering control module controls the speed of the power steering motor according to the vehicle speed and steering angle speed. By changing the power steering oil pump flow, the power steering control module controls the steering assist force.
- According to the power steering motor control, the system hydraulic pressure is transmitted from the power steering motor to power steering oil pump. The power steering oil pump is driven by the system hydraulic pressure.
- After engine start, the hydraulic pump electric power steering system performs control.
- When a malfunction occurs in the system, the fail-safe function stops the hydraulic pump electric power steering system (manual steering state) or restricts its operation (certain steering assist force). Refer to " «HYDRAULIC PUMP ELECTRIC POWER STEERING SYSTEM: FAIL-SAFE»(ref-672658-S26000427792014112400000) ".
- When the power steering function is used continuously in an extreme manner, the protective function reduces the output to the power steering motor. Refer to " «HYDRAULIC PUMP ELECTRIC POWER STEERING SYSTEM: PROTECTION FUNCTION»(ref-672658-S32788473792014112400000) ".
Scheme 1
OPERATION CHARACTERISTICS
When the steering angle speed is high or the vehicle speed is low, force is generated by increasing discharge amount from the power steering oil pump and by raising system hydraulic pressure.
Scheme 2
OPERATION PRINCIPLE
When Steering Wheel is in the Neutral Position
Scheme 3
Because the hydraulic routes open at the power steering pump, gear housing right side, gear housing left side, and reservoir tank, the hydraulic pressure applied to the right side and left side of the gear housing is equal and no steering assist force is generated.
When Steering Wheel is Rotated to the Right
Scheme 4
The hydraulic routes open from power steering pump to gear housing right side and from gear housing left side to reservoir tank, providing left direction assist force to the rack.
When Steering Wheel is Rotated to the Left
Scheme 5
The hydraulic routes open from power steering pump to gear housing left side and from gear housing right side to reservoir tank, providing right direction assist force to the rack.
ECU IDENTIFICATION
Displays the part number stored in the control unit.
Description
- In general, customers have their own criteria for a problem. Therefore, it is important to understand the symptom and status well enough by asking the customer about his/her concerns carefully. To systemize all the information for the diagnosis, prepare the interview sheet referring to the interview points.
- In some cases, multiple conditions that appear simultaneously may cause a DTC to be detected.
Scheme 6
CAN (Controller Area Network) is a serial communication line for real time application. It is an on-vehicle multiplex communication line with high data communication speed and excellent error detection ability. Many electronic control units are equipped onto a vehicle, and each control unit shares information and links with other control units during operation (not independent). In CAN communication, control units are connected with 2 communication lines (CAN-H line, CAN-L line) allowing a high rate of information transmission with less wiring. Each control unit communicate data but selectively reads required data only.
The hydraulic pump electric power steering warning lamp does not illuminate when the ignition switch is turned ON (lamp check).
Hydraulic pump electric power steering warning lamp does not turn OFF several seconds after engine started