sensor FORD KUGA 2011 1.G Repair Manual

SECTION 206-09B Anti-Lock Control - Stability Assist
VEHICLE APPLICATION:2008.50 Kuga
PA G E
CONTENTS
DESCRIPTION AND OPERATION
206-09B-2
Anti-Lock Control - Stability Assist (Component Location) .................................................
206-09B-3
Anti-Lock Control - Stability Assist (Overview) ...................................................................
206-09B-3
Overview ........................................................................\
.....................................................
206-09B-4
Testing the brakes on a roller dynamometer - 4X4 vehicles only ...................................
206-09B-4
ABS/ESP module or hydraulic control unit (HCU) ..............................................................
206-09B-4
Combined yaw rate sensor and lateral acceleration sensor / longitudinal acceleration
sensor ........................................................................\
.......................................................
206-09B-5
Front wheel sensor ........................................................................\
.....................................
206-09B-5
Rear wheel sensor ........................................................................\
......................................
206-09B-5
Opto-electronic steering wheel rotation sensor ..................................................................
206-09B-6
ESP switch ........................................................................\
.................................................
206-09B-7
Anti-Lock Control - Stability Assist (System Operation and Component Description) ........
206-09B-7
System Diagram ........................................................................\
.........................................
206-09B-8
System Operation ........................................................................\
.......................................
206-09B-9
PRINCIPLES OF OPERATION ........................................................................\
...............
206-09B-11
Component Description ........................................................................\
..............................
206-09B-?
Opto-electronic steering wheel rotation sensor ..............................................................
206-09B-?
ABS/ESP module or hydraulic control unit (HCU) ..........................................................
206-09B-?
ESP switch ........................................................................\
..............................................
206-09B-?
Combined yaw rate sensor and lateral acceleration sensor / longitudinal acceleration
sensor........................................................................\
................................................... 206-09B-?
Front wheel sensor ........................................................................\
.................................
206-09B-?
Rear wheel sensor ........................................................................\
..................................
REMOVAL AND INSTALLATION 206-09B-16
Hydraulic Control Unit (HCU) ........................................................................\
.....................
206-09B-19
Stability Assist Module ........................................................................\
................................
206-09B-21
Front Wheel Speed Sensor ........................................................................\
........................
206-09B-22
Rear Wheel Speed Sensor ........................................................................\
.........................
206-09B-23
Yaw Rate Sensor ........................................................................\
........................................
206-09B-1
Anti-Lock Control - Stability Assist
206-09B- 1
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Anti-Lock Control - Stability Assist – Overview
Overview
E96701
1
2
3
45
6
7
8
9
Description
Item
ABS/ESP module or hydraulic control unit
(HCU)
1
Front wheel sensor, left-hand side
2
Steering Wheel Rotation Sensor
3
Rear wheel sensor, left-hand side
4Description
Item
Rear wheel sensor, right-hand side
5
Combined yaw rate sensor and lateral
acceleration sensor / longitudinal
acceleration sensor
6
Wiring harness
7
G1001303en2008.50 Kuga8/2011
206-09B- 3
Anti-Lock Control - Stability Assist
206-09B- 3
DESCRIPTION AND OPERATION
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Description
Item
Front wheel sensor, right-hand side
8Description
Item
9 ESP switch
Testing the brakes on a roller dynamometer
- 4X4 vehicles only
On 4X4 vehicles a brake test on a roller
dynamometer must only be performed under the
following conditions.
• The brake test must not exceed a duration of 1 minute.
• Ignition key in position 0.
• The roller speed must not exceed 5 km/h.
ABS/ESP module or hydraulic control
unit (HCU)
E96821
1
23
The ABS/ESP module or the hydraulic control unit
(HCU) is mounted on the left-hand side of the
bulkhead. Diagnosis is performed with the aid of
a diagnostic tester.
The following components can be replaced
separately or as a unit:
• Hydraulic Control Unit (HCU)
• ABS/ESP module
• Mounting Bracket
The following must be taken into account when
removing/installing or renewing the ABS/ESP
module or the hydraulic control unit (HCU):
• Only hydraulic control units (HCU) which are pre-filled with brake fluid are available for
service operations.
• After replacing the HCU it is not necessary to bleed the system via the diagnostic tester.
• After replacing the brake fluid it is also only necessary to perform standard bleeding.
• The blanking caps/plugs must not be removed until the brake tubes are ready to be connected. • If accidentally dropped or knocked install a new
hydraulic control unit (HCU) and module
assembly.
• When the ABS/ESP module is removed/installed or replaced, it is necessary to reconfigure the
ABS/ESP module with the aid of the diagnostic
tester once all of the installation work has been
performed.
Refer to: Module Configuration (418-01 Module
Configuration, General Procedures).
Combined yaw rate sensor and lateral
acceleration sensor / longitudinal
acceleration sensor
E96822
The sensor is attached to the floor crossmember
at the front right. For vehicles with 4x4 drive, a
longitudinal acceleration sensor is also integrated
in the same housing.
The following must be taken into account when
removing/installing or replacing the combined yaw
rate sensor and lateral/longitudinal acceleration
sensor:
• Ensure the correct installation position of the yaw rate sensor and lateral/longitudinal
acceleration sensor.
G1001303en2008.50 Kuga8/2011
206-09B- 4
Anti-Lock Control - Stability Assist
206-09B- 4
DESCRIPTION AND OPERATION
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Front wheel sensor
E96823
The ABS sensor rings are built into the seals in the
front wheel bearings. The wheel sensors are joined
to the main wiring harness using a separate
connecting cable.
Rear wheel sensor
E96824
4X4:The ABS sensor rings are pressed onto the
rear drive shafts. The wheel sensors are joined to
the main wiring harness using a separate
connecting cable.
4X2: The ABS sensor rings are built into the hubs
of the rear wheel bearings. When installing a
replacement bearing, ensure that the new part is
aligned correctly. The wheel sensors are joined to
the main wiring harness using a separate
connecting cable.
Opto-electronic steering wheel rotation
sensor
E80158
G1001303en2008.50 Kuga8/2011
206-09B- 5
Anti-Lock Control - Stability Assist
206-09B- 5
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Vehicles with ESP are equipped with an
opto-electronic steering wheel rotation sensor as
an integral part of the clockspring.
The following must be taken into account when
removing/installing or replacing the opto-electronic
steering wheel rotation sensor:
• If installing a new clockspring, remove theclockspring locking screw.
ESP switch
E99006
Stability assist can be deactivated via the menu in
the instrument cluster.
G1001303en2008.50 Kuga8/2011
206-09B- 6
Anti-Lock Control - Stability Assist
206-09B- 6
DESCRIPTION AND OPERATION
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Description
Item
D.C. motor
9
Solenoid-operated pilot valve (2 off)
10
Solenoid-operated priming valve (2 off)
11
One way check valve
12
Low-pressure accumulator (2 off)
13
Solenoid-operated inlet valve (RH rear
brake)
14
Solenoid-operated inlet valve (LH front
brake)
15
Solenoid-operated outlet valve (LH front
brake)
16
Solenoid-operated outlet valve (RH rear
brake)
17Description
Item
Pressure sensor (5 off)
18
LH front brake (secondary circuit)
19
RH rear brake (secondary circuit)
20
LH rear brake (primary circuit)
21
RH front brake (primary circuit)
22
Solenoid-operated outlet valve (RH front
brake)
23
Solenoid-operated outlet valve (LH rear
brake)
24
Solenoid-operated inlet valve (LH rear
brake)
25
Solenoid-operated inlet valve (RH front
brake)
26
System Operation
The HCU features 3 operating modes:
Normal braking:
Initially, no current is supplied to
any of the solenoid-operated valves. Operating the
brake pedal produces a corresponding increase
or decrease of pressure in the brakes, through the
open pilot valves and inlet valves. If the ABS
module determines that EBD is necessary, it
energizes the inlet valves for both the rear brakes,
to isolate the brakes from any further increase in
hydraulic pressure.
ABS braking: If the ABS module determines that
ABS braking is necessary, it actuates the inlet and
outlet valves of the relevant brake and starts the
hydraulic return pump. The inlet valve closes to
isolate the brake from pressurized fluid; the outlet
valve opens to release pressure from the brake
into the accumulator and the return pump circuit.
The brake releases slightly and the wheel starts to turn again. The ABS control unit then operates the
inlet and outlet valves to regulate the hydraulic
pressure acting on the brake in order to maximize
braking effect without the wheel locking up. Control
of the valves for each wheel takes place
individually.
Active braking:
With active braking, pressure is
generated for other braking functions than the
normal and ABS braking systems, e.g. for the ESP
and TCS systems. For active braking, the ABS
module energizes the pilot valves and priming
valves, starts the return pump and energizes all of
the inlet valves. Brake fluid, drawn from the
reservoir through the master cylinder and priming
valve, is pressurized by the return pump and
supplied to the inlet valves. The ABS control unit
then actuates the inlet and outlet valves in order
to regulate the pressure for the individual brakes.
Some noise may be generated during active
braking.
G1001304en2008.50 Kuga8/2011
206-09B- 8
Anti-Lock Control - Stability Assist
206-09B- 8
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Description
Item
Battery
1
Battery junction box (BJB) in the engine
compartment
2
Generic electronic module (GEM)
3
Powertrain Control Module (PCM)
4
Instrument cluster
5
Data link connector (DLC)
6
Steering Wheel Rotation Sensor
7
ABS/ESP module or hydraulic control unit
(HCU)
8Description
Item
Combined yaw rate sensor and lateral
acceleration sensor / longitudinal
acceleration sensor
9
Front wheel sensor
10
Rear wheel sensor
11
Rear wheel sensor
12
Front wheel sensor
13
ESP switch
14
Rear brakes
15
Front brake
16
The ABS monitors the different wheel speeds of
the vehicle with the aid of wheel speed sensors.
Using the data from all of the wheel speed sensors,
the ABS module calculates the so-called reference
speed, which is a measure of the actual road
speed. The ABS module compares the individual
circumferential wheel speeds with this reference
speed when the driver initiates braking. If one or
more of the circumferential wheel speeds deviates
too far from the reference speed, this means that
slip at the affected wheels is so great that steering
stability of the vehicle is no longer ensured. The
ABS module actuates electro-mechanical valves
which influence the brake pressure at the relevant
wheels.
Like the traction control system (TCS), the ESP
system uses a large proportion of the ABS
components. In addition, there are sensors which
pick up the steering angle, the acceleration forces
acting on the vehicle and the yaw rate or yaw
moment. The sensors transmit these signals to the
combined ABS/ESP module. Using the wheel
speed and steering angle data, the ABS/ESP
module calculates the direction of travel planned
by the driver and determines the corresponding
speed-dependent lateral acceleration and yaw
moment. These values are compared with those
actual measured. If the actual lateral acceleration
and the yaw moment deviate excessively from the
target values (unstable driving characteristics), the
ABS/ESP module actuates individual brakes
selectively via the HCU (hydraulic control unit). In
addition, the engine speed is reduced by
intervention in the engine management system.
How the system works for understeer: In the
event of understeer, brake intervention occurs at
the wheels on the inside of the curve. The rear
wheel is braked heavily, so that a high amount of slip is caused. In this way, the cornering force of
the rear axle is heavily reduced and the centrifugal
force that now becomes effective turns the rear of
the vehicle back into the curve. The front wheel is
not braked as hard. The braking force that is
transmitted via the front wheel to the road surface
generates a torque with the aid of the lever arm
(vertical tire force to the vehicle's centre of gravity),
which supports the yaw moment of the vehicle.
Both measures together result in the vehicle
reverting back to the curved path intended by the
driver.
How the system works for oversteer:
In the
event of oversteer the wheels on the outside of the
curve are braked. This time, the front wheel is
subjected to a high level of slip so that the
cornering force at the front axle is reduced. The
rear wheel is not braked as heavily and, together
with the effective lever arm, results in a reduction
in the vehicle yaw moment. Both measures
together result in the vehicle being stabilized and
reverting back to the curved path intended by the
driver.
If ESP control occurs, possible ABS interventions
will be overridden as the ESP works at higher slip
rates than the ABS.
Emergency brake assist (EBA): The emergency
brake assist helps drivers in emergency braking
situations by automatically applying the brakes with
the maximum possible braking force.
If the brake pedal is pressed very suddenly, the
ABS module increases the hydraulic pressure to
all of the brakes until the threshold for ABS
intervention is reached. This applies the maximum
braking effort for the available traction. The ABS
control unit monitors inputs from the brake pedal
switch and from the pressure sensor within the
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206-09B- 10
Anti-Lock Control - Stability Assist
206-09B- 10
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HCU to check for sudden actuation of the brakes.
With the brake pedal pressed, the ABS module
triggers emergency braking if the rate of increase
of hydraulic pressure exceeds the predetermined
limit.
If the brake pedal is pressed so hard that the ABS
becomes active on the front wheels then the ABS
control unit increases the pressure to the rear
wheel brakes up to the ABS intervention threshold.
EBA operation continues until the driver releases
the brake pedal sufficiently for the hydraulic
pressure in the HCU to drop below a threshold
value stored in the ABS module.
Trailer stability control:If the vehicle is ordered
with a trailer coupling then the Trailer Stability
Control function is integrated in the ESP. The ESP
detects snaking when driving with a trailer and
reduces the speed of the vehicle and trailer through
adapted braking and, if necessary, by also reducing
the engine output until the snaking movement of
the trailer is corrected.
Roll-over protection: The ESP dynamically
determines the tipping tendency of the vehicle and
works in conjunction with the EBA system to
prevent the vehicle from tipping over during
dynamic maneuvers like lane changing or while
negotiating bends.
Emergency brake light: The emergency brake
light automatically switches on the hazard flasher
system to warn drivers of other vehicles that
emergency braking is being initiated. Based on a
defined delay value, the ABS/ESP module sends
a signal to the generic electronic module (GEM)
via the CAN data bus. The GEM activates the
hazard flasher system, that then flashes 7 times.
Prerequisites for activation of the emergency brake
light are:
• The speed is higher than 50 km/h.
• The brake pedal is being actuated.
• The deceleration is greater than 9 m/s².
To prevent activation on snow or ice, for example,
the following prerequisites must be met:
• The speed is higher than 50 km/h.
• The brake pedal is being actuated.
• ABS regulation takes place.
• The deceleration is greater than 6 m/s².
Tire pressure monitoring system: The tire
pressure monitoring system used in the Kuga is
able to detect loss of air in a tire at an early stage
and warn the driver. Because it can only compare
the behaviour of the tyres with each other, it is not possible to draw conclusions about the absolute
tyre pressure. It is also not possible to monitor the
spare tyre pressure. In order for the system to
operate correctly, the tyre pressures must be
regularly checked and corrected and the system
subsequently initialised (see below).
The tire pressure monitoring system used here,
depending on the equipment level, is built into the
anti-lock braking system (ABS) as an extra function
and therefore does not have its own sensors.
The ABS module measures the loss of pressure
in the tyres by calculation using the wheel speed
sensors of the ABS system. If a tyre loses
pressure, its diameter decreases and the speed of
the wheel therefore increases. If the ABS module
detects such a loss in pressure, it sends a signal
to the instrument cluster via the CAN bus and a
warning message is displayed in the message
centre. The warning threshold depends among
other things on the dimension of the tyres being
used, the vehicle operating conditions and the
status at the last initialisation. Since neither the
absolute tyre pressure nor the position of the tyre
is known, the pressure of all the tyres must be
checked and the system re-initialised after a tyre
pressure warning. If necessary, the cause of the
loss of pressure must be investigated.
Regular tyre pressure checks are still necessary.
The system must be initialised after a tyre is
changed, winter or summer tyres fitted, the
pressures corrected or adjusted to suit the vehicle
load. This can be done by the driver using the
driver information system. For further information,
see: Owner’s Manual.
Component Description
Opto-electronic steering wheel rotation
sensor
E80158
G1001304en2008.50 Kuga8/2011
206-09B-
11
Anti-Lock Control - Stability Assist
206-09B- 11
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The opto-electronic steering wheel rotation sensors
use light barriers for contactless scanning of a
segment disk which is connected fixedly to the
steering shaft.
E54014
1
23
4
Description
Item
Segment disk
1
Photoelectric barrier
2
Electronics
3
Electrical connection
4
Use is made of opto-electronic types of sensors
with relative and absolute steering angle sensing.
For relative steering angle sensing, changes in the
steering angle are measured exclusively by the
sensor and transmitted to the ABS/ESP module.
With the aid of other vehicle status signals (e.g.
wheel speed sensors) the module calculates the
straight ahead position of the steering. For absolute
steering angle sensing, the sensor transmits a
specific signal to the module for each steering
angle position (in relation to one turn of the steering
wheel). The straight ahead position of the steering
is therefore defined in the sensor. On an absolute
steering angle sensor, several photoelectric barrier
modules are distributed around the segment disk
at varying distances. The gaps between segments
of the segment disk are also unequal. For each specific steering angle there is therefore a specific
switch status of all photoelectric barriers.
ABS/ESP module or hydraulic control unit
(HCU)
E97648
1
2
3
Description
Item
ABS Pump Motor
1
Valve block (with low-pressure
accumulators)
2
ABS module
3
The HCU comprises the ABS module, the valve
block (with low-pressure accumulators) and the
ABS pump.
The valve block combines all of the brake pressure
control valves in one unit. Depending on the
system, either simple changeover valves or
proportioning valves (e.g. on EBD (electronic brake
force distribution) systems) are installed. The
low-pressure accumulators store the brake fluid
that is returned from the wheel brakes during the
pressure reduction phase until it is drawn back into
the system by the ABS pump.
The ABS pump is designed as a dual piston pump.
This means that two separate pump elements
assure an increase in brake pressure during control
interventions. A direct current motor drives the
pump pistons via an eccentric shaft.
The ABS/ESP module monitors the input signals
of all sensors and actuates the electro-magnetic
brake pressure valves and the ABS pump as
required. For reasons of safety, the module is of
the redundant type, whereby processing of the
signals is carried out via two separate processors
that also monitor each other.
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206-09B- 12
Anti-Lock Control - Stability Assist
206-09B- 12
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ESP switch
E99006
Stability assist can be deactivated via the menu in
the instrument cluster. The stability assist functions
are deactivated when the Set switch is actuated.
The ABS control module makes the stability assist
functions available once more when the Set switch
is actuated again. The stability assist function is
automatically reactivated when the ignition is
switched on.
The electronic EBA is a constant function and will
remain active even if the ESP has been switched
off.
Combined yaw rate sensor and lateral
acceleration sensor / longitudinal
acceleration sensor
E96822
The heart of the combined yaw rate sensor and
lateral acceleration sensor/longitudinal acceleration
sensor is a small, double-sided tuning fork made
of a piezo crystal (A). The exciter side of this tuning
fork is set to a resonance of 11 kHz with the aid of
an alternating current. The measuring side of the
tuning fork features a resonance frequency of 11.33
kHz and therefore does not vibrate (B). Since,
under influence of an external accelerating force,
a vibrating mass reacts slower than a comparable
mass that is not vibrating, the tuning fork twists
within itself with rotational movement being
imparted on the sensor (C). This rotation results
in a change in the charge distribution in the Piezo
element, which is subsequently picked up and
converted into an electronic signal by electronics
integrated into the sensor. This electronic signal is
then sent to the ESP module. The ESP module
evaluates these data and takes into account the
other input data (vehicle speed, wheel speed)
before deciding whether the ESP function is
required.
G1001304en2008.50 Kuga8/2011
206-09B-13
Anti-Lock Control - Stability Assist
206-09B- 13
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