2004 DAEWOO LACETTI ACC

6B – 8IPOWER STEERING PUMP
DAEWOO V–121 BL4
GENERAL DESCRIPTION
AND SYSTEM OPERATION
POWER STEERING PUMP
The power steering pump is a multivaned hydraulic pump.
The serpentine accessory drive belt on the engine drives
the power steering pump.The power steering pump provides the hydraulic pressure
to the power steering gear.
The power steering gear uses the hydraulic pressure to
assist in steering the vehicle.
The power steering system uses a remote reservoir in or-
der to make available more space in the engine compart-
ment.

6C – 18IPOWER STEERING GEAR
DAEWOO V–121 BL4
3. Turn the steering wheel so that the upper pinch bolt
is accessible. Remove the upper pinch bolt from
the universal joint on the intermediate shaft.
4. Remove the nuts from the dash seal retaining ring
and remove the dash seal retaining ring.
5. Remove the coupling from the power steering gear
and pull the intermediate shaft out of the engine
compartment.
Installation Procedure
1. Install the intermediate shaft into the vehicle.

POWER STEERING GEAR 6C – 33
DAEWOO V–121 BL4
GENERAL DESCRIPTION
AND SYSTEM OPERATION
POWER RACK AND PINION
The power rack and pinion steering system has a rotary
control valve that directs hydraulic fluid coming from the
hydraulic pump to one side or the other side of the rack pis-
ton. The integral rack piston is attached to the rack. The
rack piston converts hydraulic pressure to a linear force
that moves the rack left or right. That force is then trans-
mitted through the tie rods to the steering knuckles, which
turn the wheels.
If power rack and pinion steering is not available, manual
rack and pinion control is used; however, with this system,
more steering effort is required. The movement of the
steering wheel is transferred to the pinion. The rotary
movement of the pinion is then transferred through the pin-
ion threads, which mesh with teeth on the rack, thereby
causing the rack to move in a linear direction.
A vane–type of hydraulic pump provides hydraulic pres-
sure for both steering systems.
SPEED SENSITIVE POWER
STEERING SYSTEM
The speed sensitive power steering (SSPS) system varies
the driver effort required to steer as the vehicle speed
changes. At low speeds, the system provides maximum
power assist for easy turning and parking maneuvers. At
higher speeds, the steering power is reduced to provide
the driver with firmer steering and directional stability. The
SSPS system accomplishes this by reducing the amount
of power steering fluid flow from the power steering pump
to the power steering gear as the vehicle speed increases.
When the vehicle is stationary, the SSPS system provides
maximum fluid flow to the steering gear. As the vehicle
speed increases, the fluid flow to the steering gear is de-
creased.
Control Module
The SSPS control module processes the vehicle speed in-
formation from the engine control module (ECM) and uses
the steering wheel rotation sensor to provide a control sig-
nal to the electronic variable orifice (EVO) actuator located
on the power steering pump.
Electronic Variable Orifice (EVO) Actuator
The electronic variable orifice (EVO) actuator is located on
the power steering pump and contains a solenoid– oper-
ated pintle valve. Fluid leaving the pump passes through
an orifice in the actuator tip. When the EVO actuator is
powered by the SSPS control module, the pintle moves
into the orifice and reduces the power steering fluid flow.As the vehicle speed increases, current from the SSPS
control module increases, and the pintle blocks more and
more of the orifice.
Steering Wheel Rotation Sensor
The steering wheel rotation sensor is located at the end of
the steering column housing and is used to send a signal
to the controller when abrupt or evasive steering maneu-
vers are needed.
Power Steering Pressure Hose
SSPS vehicles have a specific pressure hose assembly
which includes an in–line check valve in the rack and pin-
ion assembly. This reduces the amount of steering wheel
”kick” when driving over irregular road surfaces while oper-
ating at speeds with reduced flow rate and pressure.
Power Rack and Pinion
Except for differences in valve machining, the design of
the SSPS power rack and pinion assembly is the same as
for the a non–SSPS system. The steering wheel move-
ment is transferred to the pinion via the intermediate shaft.
The pinion moves the rack left or right through meshing the
pinion and the rack teeth. The force is then transmitted
through the tie rods and steering knuckle to steer the
wheels.
The power rack and pinion steering system has a rotary
control valve which directs the hydraulic fluid from the
power steering pump to one side or the other side of the
rack piston. The piston is attached to the rack and uses hy-
draulic pressure to move the rack left or right. The rotary
control valve regulates the degree of assist by responding
to the driver’s torque input.
If hydraulic assist is not available, manual control is main-
tained. However, under this condition, more steering effort
is required.
Power Steering Pump
The standard vane–type pump, which provides hydraulic
pressure for the system, incorporates a special discharge
fitting to hold the EVO actuator.
System Operation
System operation originates with input from the vehicle
speed sensor via the engine control module to the SSPS
control module. The SSPS control module sends a signal
to the SSPS actuator to vary the rate of fluid flow output
by the power steering pump.
Circuit Operation
The SSPS system uses inputs from the speed sensor and
steering wheel rotation sensor to the SSPS controller to
determine the desired amount of power steering assist.
The SSPS control module constantly compares the
amount of current flowing through the EVO actuator to the
desired current it has calculated. The EVO actuator has a
pintle that moves in and out of an orifice, regulating power

6C – 34IPOWER STEERING GEAR
DAEWOO V–121 BL4
steering fluid flow. The SSPS control module can change
the amount of current flowing through the EVO actuator by
varying the output duty cycle. If the EVO actuator is dis-
connected, the pintle will be pulled out of the orifice for
maximum power steering assist.
The SSPS control module has the ability to detect faults
in the steering wheel rotation sensor, the EVO actuator, or
the circuitry to those components. Any default detected
will cause the power steering assist to remain at maximum
with the pintle in its normally retracted position for all
speeds.
When the system is operating normally, increasing the ve-
hicle speed will decrease power steering assist, allowing
the driver to have improved road feel and directional stabil-
ity. When sudden steering wheel turns are made, as in
evasive maneuvers, they are detected by the SSPS con-trol module through the steering wheel rotation sensor.
When detected, the SSPS control module reduces current
to the EVO actuator, allowing greater power steering as-
sist.
SSPS (Speed Sensitive Power Steering) is to control pow-
er steering effort properly according to varying conditions
for both convenience and safety.
At low speed or standstill, power steering effort becomes
light to provide easy steering. On the contrary, at high
speed, power steering effort becomes heavy to provide
stable steering.
SSPS offered to LACETTI is EVO (Electric Variable Ori-
fice) type, which controls steering effort by modulating
pressurized fluid supply to the steering unit from the power
steering pump.
Steering wheel rotation sensor is installed at the bottom of
the steering column.
This sensor detects steering wheel rotation which is used
to calculate the angle speed of the steering wheel by
SSPS module.
If the angle speed was big enough for intervention into nor-mal steering force control during high vehicle speed, which
means a driver made an evasive steering maneuver to
avoid an accident, SSPS module would supply enough
steering support.
The sensor consists of a variable resistor.

POWER STEERING GEAR 6C – 37
DAEWOO V–121 BL4
[Vehicle Speed – Actuator Current Relation]
SOLENOID RESISTANCE
13 W
The control module is installed on the right side of the au-
dio and can be accessible after the glove box is removed.
It receives signals from the vehicle speed sensor and the
steering wheel rotation sensor and processes them to de-
cide proper fluid flow through the actuator.
It also has a self–diagnosis. If it detects any malfunction,
it starts default mode, which is basically actuator full open
for light steering effort.
TERMINALCOLORFUNCTION
1SBActuator Low
2VActuator High
3BWSteering Wheel Sensor Ground
4–Not used
5GrSteering Wheel Sensor 5V ref.
6GWVSS
7–Not Used
8PIGN ON
9BrWarning Lamp
10BWGround
11–Not Used
12–Not Used
13LDiagnosis
14SBSteering Wheel Sensor Signal

STEERING WHEEL AND COLUMN 6E – 11
DAEWOO V–121 BL4
2. Install the intermediate shaft onto the steering col-
umn. Refer to ”Steering Column” in this section.
3. Connect the steering wheel rotation sensor electri-
cal connector.
4. Install the upper and the lower instrument trim pan-
els. Refer to Section 9E, Instrumentation/Driver
Information.
5. Connect the negative battery cable.
STEERING WHEEL WITHOUT SIR
Tools Required
KM–210–A Steering Wheel Puller
Removal Procedure
1. Disconnect the negative battery cable.
2. Rotate the steering wheel to allow access to the
steering wheel horn cap screw. Remove the horn
cap screw.
3. Rotate the steering wheel to allow access to the
other steering wheel horn cap screw. Remove the
horn cap screw.
4. Remove the steering wheel horn cap and discon-
nect the horn leads.
5. Remove the steering wheel nut and the retaining
clip.

6E – 12ISTEERING WHEEL AND COLUMN
DAEWOO V–121 BL4
Important : In order to install the steering wheel correctly,
match–mark the steering column shaft to the steering
wheel.
6. Remove the steering wheel using the steering
wheel puller KM–210–A.
7. Unclip the contact ring from the steering wheel, if
necessary.
Installation Procedure
1. Clip the contact ring on the steering wheel, if nec-
essary.
2. Align the match marks on the steering wheel and
the steering column shaft.
3. Install the retaining clip and a new steering wheel
nut.
Tighten
Tighten the steering wheel nut to 38 NSm (28 lb–ft).
4. Bend the tabs to secure the retaining clip.
5. Connect the horn leads and install the steering
wheel horn cap.
6. Rotate the steering wheel to allow access to the
steering wheel horn cap screw. Install the horn cap
screw.
7. Rotate the steering wheel to allow access to the
other steering wheel horn cap screw. Install the
horn cap screw.
Tighten
Tighten both steering wheel horn cap screws to 4.5
NSm (40 lb–in).
8. Connect the negative battery cable.

6E – 14ISTEERING WHEEL AND COLUMN
DAEWOO V–121 BL4
4. With the key in the ignition turned to the position
designated ACC, remove the lock cylinder by
pressing down the detent spring and pulling the
lock cylinder out of the switch cylinder housing.
5. Remove the ignition switch retaining screw.
6. Disconnect the wiring and remove the ignition
switch.
Installation Procedure
1. Install the ignition switch with the ignition switch
retaining screw.
Tighten
Tighten the ignition switch retaining screw to 2.5 NSm
(22 lb–in).
2. Connect the wiring to the ignition switch.
3. Install the lock cylinder.
4. Connect the electrical connector for the immobilizer
detection unit.
5. Install the upper and the lower steering column cov-
er panel with the screws.
Tighten
Tighten the upper and the lower steering column cov-
er panel screws to 2.5 NSm (22 lb–in).
6. Connect the negative battery cable.