Operation Principle

When System is Normal (Neutral)

Fig 1: Hybrid EPS System Operation Diagram (System Normal At Neutral Position)

Courtesy of NISSAN NORTH AMERICA, INC.

Name	Current application	Open/closed
Flow connection valve	Current applied	Closed

Because the power steering motor is not being operated, no discharge pressure is generated by the power steering oil pump and no steering assist force is generated.

When System is Normal (During Steering)

Fig 2: Hybrid EPS System Operation Diagram (System Normal During Steering)

Courtesy of NISSAN NORTH AMERICA, INC.

NOTE: The illustration shows the hydraulic path during steering to the right. During steering to the left, the motor turns in the opposite direction and the hydraulic path is reversed.

Name	Current application	Open/closed
Flow connection valve	Current applied	Closed

The power steering control module controls the power steering motor so that the power steering oil pump generates hydraulic pressure according to the vehicle speed in the same direction as the steering.
The hydraulic pressure generated by the power steering oil pump is applied to the left side of the cylinder, assisting the rack in the left direction.

When System Malfunction Occurs (During Steering)

Fig 3: Hybrid EPS System Operation Diagram (System Malfunction Occurs During Steering)

Courtesy of NISSAN NORTH AMERICA, INC.

NOTE: The illustration shows the hydraulic path during steering to the right. The path is reversed during steering to the left.

Name	Current application	Open/closed
Flow connection valve	Current not applied.	Open

When a system malfunction occurs and the power steering control module stops control of the power steering oil pump, the power steering control module shuts off the current to the flow connection valve, opening the valve.
When the flow connection valve opens, the cylinder left/right hydraulic paths are bypassed, allowing steering even when the power steering oil pump is stopped.