Ford Galaxy / Ford S-MAX. Manual — part 93

8. Lower the vehicle.

Power Steering - Power Steering

S-MAX/Galaxy 2006.5 (02/2006-)

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Description and Operation

Electro-hydraulic power steering (EHPS)

The EHPS system uses an electrically driven hydraulic pump and a conventional rack and
pinion steering gear.

Using signals from the engine speed sensor, the vehicle speed sensor and the steering
wheel rotation sensor, the EHPS control module uses a 3 dimensional look up table to
adjust the turning speed of the pump.

For the EHPS pump to operate, the ignition must be in position II and the engine speed
signal must show a value greater than 800 rpm.

Description

Pump speed (rev/min)

Steering angle rate (degrees/second)

Road speed (km/h)

In more than 85% of all driving situations the EHPS pump operates at standby speed and
consumes less than 10A. EHPS pump speed can quickly increase to full turning speed when
steering manoeuvres require it.

Steering wheel rotation sensor

The steering wheel rotation sensor is attached to the clockspring and monitors the speed
with which the steering wheel is turned. This information is then sent via the control are
network (CAN) bus to the EHPS control module.

Item

A

B

C

Part Number

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Description

Clockspring

Steering wheel rotation sensor

EHPS pump

The power steering pump comprises an electric motor, hydraulic pump, power steering fluid
reservoir and a power steering fluid reservoir extension to maintain the fluid level in the
reservoir and to refill the system during service.

Description

EHPS pump reservoir extension

EHPS pump

A pressure relief and check valve is built into the EHPS pump housing which limits the
hydraulic fluid pressure to a maximum of 125 bar. The check valve will allow trapped air to
vent the EHPS pump when the EHPS pump is not operating.

Item

1

2

Item

1

2

Part Number

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-

Part Number

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-

Description

Power steering fluid reservoir

Power steering fluid reservoir clamp

Motor housing

Rubber mountings

EHPS control module

Item

1

2

3

4

5

Part Number

-

-

-

-

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