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ESP (Electronic Stability Program)

1 Chonan Technical Service Training Center

ESP(Electronic Stability Program)

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CONTENTS

1. BASIC PHYSICS OF DRIVING DYNAMICS --------------------------------

2. ESP GENERAL ---------------------------------------------------------------------

3. JM ESP SYSTEM ------------------------------------------------------------------

4. ESP CONTROL MODULE -------------------------------------------------------

5. HYDRAULIC CONTROL UNIT --------------------------------------------------

6. INPUTS AND OUTPUTS ---------------------------------------------------------

7. INPUTS -------------------------------------------------------------------------------

8. OUTPUTS ----------------------------------------------------------------------------

9. DIAGNOSIS & FAILSAFE --------------------------------------------------------

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1. BASIC PHYSICS OF DRIVING DYNAMICS

STOPPING DISTANCE

The stopping distance depends on the vehicle weight and the speed at which the vehicle travels

when the brakes are first applied.

This also applies to vehicles equipped with ABS. Although ABS attempts to adjust an optimum

braking force at each wheel, the forces which take effect between tires and road surface are so

high that even wheels equipped with ABS may squeal and leave rubber on the road. The skid mark

produced by an ABS brake application may clearly show the tread pattern of the tire.

However, in the event of an accident, the speed at which the vehicle was traveling cannot be

concluded from the skid mark of an ABS vehicle because any such mark will be clearly visible at

the start of brake application only.

BRAKING FORCE

Depressing the brake pedal causes the braking force to rise until it reaches a maximum, after

which it drops until the wheel locks.

BRAKING FORCE AT A WHEEL

The maximum braking force that can be achieved at any wheel depends upon the load on the

wheel and the frictional grip between tire and road surface, which is expressed as the coefficient of

adhesion. If the coefficient of adhesion is low, the braking force that can be achieved is very low.

You will probably be familiar with this situation from driving on winter roads. With a high coefficient

of adhesion on a dry road, the braking force that can be achieved is substantially higher. The

maximum braking force that can be achieved can also be calculated.

MAXIMUM BRAKING FORCE

FBmax = wheel load Fwheel x coefficient of adhesion

However, the calculated braking forces do no provide a

sufficiently accurate description of what happens during

braking.

The calculated values are only valid if the wheel does not

lock. If a wheel locks, adhesion changes to sliding friction,

which exerts less deceleration. In technical literature, this

loss of friction is described as slip.

Fwheel

Brake force on a wheel

FB

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CORNERING FORCE

The cornering force is highest when the wheel is rolling freely with no slip. Braking causes the

cornering force to drop to zero when the wheel locks (slip=100%).

SLIP

Brake slip is the difference between the vehicle speed and the circumferential speed of the wheel.

The slip is highest (100%) when the wheel locks and lowest (0%) when the wheel rotates unbraked.

While vehicle driving or braking, complex physical forces occurs in the tires contact area with the

road. The tires rubber elements become distorted and are exposed to partial sliding movements,

even if the wheel has not yet locked.

The slip can be calculated from the vehicle speed Vvhc and the wheel speed Vwhl using the

following equation:

S = (Vvhc - Vwhl) / Vvhc x 100%

TYPICAL SLIP CURVES

The picture shows coefficients of adhesion for various road surfaces. The typical shape of the

curves is always the same, with one exception: the curve for new snow rises when the slip reaches

100%.

Concrete(dry)

Concrete(wet)

Snow

Ice

Concrete(dry)

Concrete(wet)

Snow

Ice

On a vehicle without ABS, the wheel locks when

braked, causing a wedge of loose surface

material or new snow to build up in front, resulting

in a higher resistance and a shorter stopping

distance.

If the vehicle is equipped with ABS, the stopping

distance cannot be reduced because the wheel

will not lock. On loose surface material or newsnow, the stopping distance of a vehicle with ABS

is longer than that of a vehicle without ABS. This

is a physical phenomenon for which the anti-lock

braking system as such cannot be blamed.

However, as already mentioned, ABS is not

concerned with stopping distance, but with

steerability and driving stability, permitting you to

steer around an obstacle. A vehicle without ABS is

not steerable when the wheels lock.

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ABS WORKING RANGE

The working range starts just before the braking force reaches its maximum and ends when the

maximum is reached, because this is the point where the unstable range starts in which control is

no longer possible. ABS controls pressure modulation in such a manner that the braking force

always stays below a limit where a sufficiently high proportion is still available for cornering. With

ABS, only truly reckless driving can move us out of the Kamm circle.

KAMMS CIRCLE

Before we discuss the Kamm circle, you should know that a tire cannot transmit more than 100%

of the forces to which it is subjected. For the tire it is all the same whether you need the 100% in

the braking direction or in the effective direction of the lateral force during cornering, for example. If

you enter a bend too fast and the tire needs the full 100% which it can transmit as cornering force,

B R

C

Longitudinal force

Lateral force

Kamms frictional force

ABS working range

1000

Slip (%)

Braking

and

cornering

force

Corneringforce

Brakingforce

ABS working range

1000

Slip (%)

Braking

and

cornering

force

Corneringforce

Brakingforce

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it cannot transmit an additional braking force. The car will leave the road in spite of ABS. Kamms

circle helps us to visualize the relationship between barking force (B) and cornering force (C). To

demonstrate our point, we place a road wheel into the circle:

As long as the acting forces and the resultant force (F) stay within the circle, the vehicle is

directionally stable. If one force leaves the circle, the vehicle leaves the road.

OVERSTEERING

When the rear tires lose traction before the front tires, a car is oversteering. Recovery from an

oversteer situation must be quick since directional control can be lost.

Oversteering causes the tail end of the vehicle to swerve toward the outer side of the band (typical

of rear wheel drive vehicles).

UNDERSTEERING

When the front tires lose traction before the rear tires, a car is understeering. Instinctively, a driver

will compensate for understeer simply by turning the steering wheel further.

Understeering pushes the front wheels toward the outer verge of the bend (typical of front wheel

drive vehicle).

SLIP ANGLE

Slip angle is the deviation of a wheel between wheel deflection (steer angle) and actual course.

SIDESLIP ANGLE

Sideslip angle (attitude angel) is the deviation of the vehicle from its longitudinal axis is the

direction of travel.

YAW RATE

The yaw rate is a measure of the speed with which a vehicle turns about its vertical axis (swerving).

LATERAL ACCELERATION

Point of acceleration

Oversteering

Understeering

Center point

Point of acceleration

Oversteering

Understeering

Center point

[Oversteering & Understeering]

Increasing the vehicles speed at this

point causes the vehicle to move either

outside the original circle due to

Understeering, or inside the original

circle due to Oversteering

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Lateral acceleration acts at right angles to the direction of travel and occurs during cornering. It is a

measure of the cornering speed.

STEERING ANGLEThe steering angle equals the wheel deflection and represents the course desired by the driver.

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2. ESP GENERAL

ABS IN ADD ON DESIGN (INTEGRATED TYPE)

With these systems, a hydraulic ABS control unit is inserted into the hydraulic braking system

between tandem master cylinder and the wheel brakes. By adding wheel sensors with gear wheels

and an electronic ABS control unit, the system is converted into an electronic anti-lock braking

system.

The system consists of the following conventional components:

- Brake booster

- Tandem master cylinder

- Wheel brakes (disc or drum)

- Hydraulic ABS control unit

- Electronic ABS control unit

- Wheel sensors with tone wheels

[ABS construction]

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TRACTION CONTROL SYSTEM (BTCS/FTCS)

This system is an extension of the well-known ABS function to incorporate BTCS (Brake

Intervention Traction Control System) and FTCS (Full Traction Control System) which controls

engine torque.

ESP (ELECTRONIC STABILITY PROGRAM)

Combines the ABS and TCS components with additional sensors monitoring yaw, lateral

acceleration and the drivers intention (steer angle sensor).

** EESSPP: ABS + TCS + AAYYCC(AActive YYaw CControl)

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3. JM ESP SYSTEM

JM ESP is model MGH-25 developed by MANDO Corp.. ESP recognizes critical driving conditions,

such as panic reactions in dangerous situations, and stabilizes the vehicle by wheel-individual

braking and engine control intervention with no need for actuating the brake or the gas pedal.

ESP adds a further function known as Active Yaw Control (AYC) to the ABS, TCS, EBD functions.

Whereas the ABS/TCS function controls wheel slip during braking and acceleration and, thus,

mainly intervenes in the longitudinal dynamics of the vehicle, active yaw control stabilizes the

vehicle about its vertical axis. This is achieved by wheel-individual brake intervention and

adaptation of the momentary engine torque with no need for any action to be taken by the driver.

ESP essentially consists of three assemblies: the sensors, the electronic control unit and actuators.

Sensors measure the position of the steering wheel, the pressure in the master brake cylinder, the

yaw velocity (yaw rate) and the acceleration transverse to the vehicle (lateral acceleration). Thismakes it possible to compare the drivers intention with the momentary vehicle behavior so that in

the event of interfering deviations with adverse affect on driving safety the electronic control unit

can initiate appropriate corrective action.

The electronic control unit incorporates the technological experience accumulated in connection

with the MGH-10/20 system, but has been substantially expanded in terms of capacity and

monitoring concept in order to permit the additional sensor signals and arithmetic operations to be

processed and converted into corresponding valve, pump and engine control commands. Of

course, the stability control feature works under all driving and operating conditions. Under certain

driving conditions, the ABS/TCS function can be activated simultaneously with the ESP function inresponse to a command by the driver.

In the event of a failure of the stability control function, the basic safety function, ABS, is still

maintained.

APPLICATION TABLE OF JM ABS/TCS/ESP (O: Option item, S: Standard item)

REGION

SYSTEM

AUS

ABS

TCS

ESP

O/S(GLS) S O(4WD)

O/S(GLS

4WD)

O(2.7 V6

GLS)

O

O(4WD) O

O(GLS only)

O/S(GLS

4WD)

NORTH

AMERICA

GENERAL

AREA

MIDDLE

EAST

EC

January 2004

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4. ESP CONTROL MODULE

This unit has the functions as follows.

- Input of signal from Pressure sensor, Steering angle sensor, Yaw & Lateral G sensor, Wheel

speed sensors

The signal produced by the sensors are evaluated in the electronic control unit. From the

information received, the control unit must first compute the following variables:

- Control of braking force / traction force/ yaw moment

- Failsafe function

- Self diagnosis function

- Interface with the external diagnosis tester

SPECIFICATION

- OPERATING VOLTAGE RANGE : DC 10 ~ 16V

- OPERATING TEMPERATURE RANGE : -40 ~ 110

- CONSUMPTION CURRENT

a. BAT 1 Max: 30A(ABS/TCS) , 40A(ESP)

b. BAT 2 Max: 30A

- DARK CURRENT: Max. 1.0mA

- IGN RATED CURRENT: Max. 300mA

A : INLET VALVE (FR)

B : INLET VALVE (RL)

C : INLET VALVE (RR)

D : INLET VALVE (FL)

E : OUTLET VALVE (FR)

F : OUTLET VALVE (RL)

G : OUTLET VALVE (RR)

H : OUTLET VALVE (FL)

I : ELECTRIC SHUTTLE VALVE (ESV-R)

J: ELECTRIC SHUTTLE VALVE (ESV-L)

K:TRACTION VALVE(TCR)

L: TRACTION VALVE(TCL)

M: MOTOR(+)

N: MOTOR(GND)[ESPCM]

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[ESPCM BLOCK DIAGRAM]

[TCSCM BLOCK DIAGRAM]

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[ABSCM BLOCK DIAGRAM]

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BASIC FUNCTIONS OF ESP

WHAT TRIGGERS AN ESP INTERVENTION

A criterion for ESP intervention exists when the yaw rate sensor senses an oversteering or

understeering tendency of at least 4/s (threshold depends on speed). If the plausibility analysis

shows the same situation, action is taken to stabilize the driving condition.

IN THE EVENT OF OVERSTEERING

Braking intervention takes place at the wheels on the outside of the bend. Most of the braking force

is introduced via the front wheel, which is caused to slip up to 50% so that the centrifugal force

contributes to stabilizing the vehicle. In this case, the ABS logic is blotted out by ESP for the

wheels with ESP intervention.

If over-steering begins to start while turning, vehicle moves far inward. Then, over-steering control

activates. When the braking force is applied to outer wheels, yaw moment in opposite direction is

generated to compensate the over-steer. Therefore, vehicle moves as the driver intends.

Compensatingyawing moment

Compensatingyawing moment

Brake force

Brake force

[In the event of understeering]

If the car is understeered with the front wheelspushing outward, a compensating yawingmoment which returns the car body to thedesired curse is built up by braking the rearwheel on the inside of the bend.

[In the event of oversteering]

If a swerving tail end shows that the car is indanger of oversteering, the front wheel onthe outside of the bend is braked. Thecompensating yawing moment, which nowacts in the clockwise direction, turns the carback into the desired direction.

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IN THE EVENT OF UNDERSTEERING

Braking intervention takes place at the wheels on the inside of the bend. In this case, the greater

force is introduced via the rear wheel so that the lateral force is selectively reduced in exact does

to stabilize the vehicle. The ABS logic is again blotted out by ESP for the wheels with ESP

intervention.

When under-steering begins while the vehicle turning, vehicle slips outward regardless of driversintention. Then, under-steering control starts. The control module generates the braking force at

the inner wheel of the vehicle and yaw moment generates, in which vehicle tries to turn to inner

side of the road. Then, vehicle moves as the driver intends.

FL wheel brakingNon-control

Control

Normaldirection

Generated Moment

FL wheel brakingNon-control

Control

Normaldirection

Non-control

Control

Normaldirection

Generated Moment

Without control

Control

RR wheel braking

Generated Moment

Normal

direction

Without control

Control

RR wheel braking

Generated Moment

Normal

direction

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5. HYDRAULIC CONTROL UNIT

In the hydraulic control unit of the MGH-25 system,

- Pump

- Valve block

Are grouped together in one housing, forming one compact

unit with the electric motor. The pump and valve concepts

are largely identical with the proven MGH ABS production

system.

The pump itself is a silenced two-circuit pump driven by an

electric motor. The solenoid valves which modulate the pressuring during ESP control are alsointegrated.

Peculiar things to MGH-25 ESP hydraulic are that shuttle valve is changed to solenoid type from

hydraulic type and TC valve is repositioned. This is because ESP system controls the brake

pressure of 4 wheels respectively while driving unlike the TCS which controls the brake pressure of

2 driving wheels in operation.

For a diagonal brake circuit split (K), four pairs of valves (4 inlet valves, 4 outlet valves) are

provided for modulating the pressure at the wheels plus two isolating valves and two electrically

operated shuttle valves.

The common housing furthermore accommodates a low-pressure accumulator and a silencing

chamber for each brake circuit.

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HYDRAULIC CIRCUIT

INLET SOLENOID VALVE (NO VALVE)

This valve connects or disconnects the hydraulic path between master cylinder and the wheel

cylinders. It remains open normally but it is closed when the dump and hold mode begins during

ABS operation. Check valve is to help the brake fluid returning from the wheel cylinder to the

master cylinder when the brake pedal is released.

OUTLET SOLENOID VALVE (NC VALVE)This valve is normally closed but it is opened to release the wheel cylinder pressure when a dump

mode begins.

SHUTTLE VALVE

The valve type is changed to the solenoid valve type for MGH-25 model from the hydraulic valve

type that is used in TCS. When the ESP is in operation, the brake fluid should be supplied to the

motor pump from the M/C via the shuttle valve to generate the brake pressure. This solenoid valve

is closed and blocks the passage when a brake pedal is applied.

[MGH-25 ESP hydraulic circuit]

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TRACTION CONTROL VALVE (TC VALVE)

In case of a normal condition, this valve remains open and the brake pressure from the M/C can be

applied to the front wheel via TC valve. While TCS or ESP in operation, TC valve is closed and the

generated pressure by motor delivers to wheel cylinders without returning to the master cylinder.

TC valve includes a relief valve and a check valve. When excessive pressure is supplied from the

motor, relief valve is opened and the pressure is relieved.

HYDRAULIC CIRCUIT DIFFERENCE BETWEEN ESP AND TCS

ESP system controls the brake pressure of 4 wheels respectively while driving unlike the TCS

which controls the brake pressure of 2 driving wheels in operation.

HYDRAULIC SHUTTLE VALVE AND ELECTRIC SHUTTLE VALVE (SOLENOID VALVE)

DIFFERENCES BETWEEN THE HYDRAULIC SHUTTLE VALE USED FOR ABS/TCS AND

THE ELECTRIC SHUTTLE VALVE USED FOR ESP:

Like the hydraulic shuttle valve of an MGH-10/20 TCS system, the electric shuttle valve is

located between the suction side of the pump and the master cylinder.

With the braking system depressurized, the hydraulic shuttle valve is open and closes as soon

as a pressure between 1.5 and 2.5 bar is reached in the braking system. The hydraulic shuttlevalve opens automatically when the pressure drops below 1.5 bar.

The electric shuttle valve is closed at all times, regardless of the pressure applied. It can only

be opened by the electronic control unit.

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MOTOR PUMP

AIR BLEEDING IN THE WORKSHOP LOCATION

When the ESP hydraulic unit is replaced in the workshop, no special action is required because

replacement parts are always delivered prefilled so that the pump circuit need not be bled

Suction

Dump

Suction (right side of pump)

The pump piston moves to the left and the

suction valve opens and brake fluid is sucked in.

Pressure increase (left side of pump)

The left piston moves to the left and the pressure

valve opens and pressure is built up.

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HYDRAULIC FLOW

In braking position

In this position, the inlet valve and the TCS

valve are open, the outlet valve and the

electrically operated shuttle valve remain

closed.

In ESP control (pressure increase)

The on/off booster builds up a pressure of

approximately 10 bar in order to enable the

ESP pump to suck brake fluid at low

temperatures. In this position, the inlet valve

is driven in a pulsed cycle. The TCS valve is

closed. The outlet valve remains closed. The

electrically operated shuttle valve is opened.

The hydraulic pressure is led to the wheel

brakes which are to be applied for a brief

period of time..

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6. INPUTS AND OUTPUTS

[ESP Components]

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7. INPUTS

ACTIVE WHEEL SPEED SENSOR (HALL IC TYPE)

- Type: Hall Effect

- Components: HALL IC, Capacitor, Magnet

- Output signal: Digital (Open Collector Type circuit integrated)

- Good characteristics against temperature variation and noise

- Low RPM Detection: 0 RPM can be detected

- Air gap sensitivity: stable output pulse width against air-gap

change

- Supplying power: DC 12V

Generated output current from the sensor is 7mA or 14mA. So in

order to check the sensor function, the output current needs to be

check. If the current measurement is not available, the output

voltage waveform can be checked.

The wheel sensors are constantly checked electrically by the

control module. In addition, the sensor signal is checked while the

vehicle is running. If there is a malfunction or a non-plausible

physically possible signal, ABS and ESP is switched off and the

ABS warning lamp and ESP OFF warning lamp is switched on.

MAX TYPICAL MIN

LOWER SIGNAL ILOW (mA) 5.9 7 8.4

UPPER SIGNAL IHIGH (mA) 11.8 14 16.8

SIGNAL RATIO IHIGH / ILOW

OUTPUT SIGNAL

OPERATING FREQUENCY

OPERATING DUTY

1.85 or more

1 ~ 2500 Hz

30~70%

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Comparison between the passive wheel sensor and the active wheel sensor

YAW RATE SENSOR & LATERAL ACCELERATION SENSOR

Dull (frequency change)Max.: 3.0mm

Sensitive (Vout1/(gap)2)

Max.: 1.3mmAir-gap

Sensitivity

Nearly 0 KPH(Intelligent Type)

Cannot be detected at low speed ( 3km/hor less)Zero Speed

Smaller(possibly smaller by 40~50%)LargerSensor Size

GoodPoorAnti-noise

-40 ~ +150 -40 ~ +125 Temp.

GoodMediumMass production

GoodImpossibleOne Chip

Active sensorPassive sensorItem

Dull (frequency change)Max.: 3.0mm

Sensitive (Vout1/(gap)2)

Max.: 1.3mmAir-gap

Sensitivity

Nearly 0 KPH(Intelligent Type)

Cannot be detected at low speed ( 3km/hor less)Zero Speed

Smaller(possibly smaller by 40~50%)LargerSensor Size

GoodPoorAnti-noise

-40 ~ +150 -40 ~ +125 Temp.

GoodMediumMass production

GoodImpossibleOne Chip

Active sensorPassive sensorItem

[Principle of Active Wheel Speed Sensor]

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- Operating Voltage: 5 0.25 V

- Operating Temperature : - 40 ~ 85 G-Sensor Range : - 1.5 ~ 1.5 gYaw-Sensor Range: - 75

~ +75 /secZero Output Voltage: 2.5 VOutput Voltage Range: 0.5 ~ 4.5 V

* Driving through a left curve leads to a more positive output signal

c. Hi-scan data

[Output Characteristics of Acceleration][Output Characteristics of Yaw Rate]

Left turn

Right turn

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STEERING ANGLE SENSOR

Steering sensor signal will be used as the input signal for anti-roll control. The steering sensor uses

LED and photo-transistor, and sensor A (ST1) and sensor B (ST2) are installed steering wheel. A

Slit plate is installed between the photo-transistor and the LED. The slit plate has 45 holes, so it will

rotate when the steering wheel rotates. The photo-transistor operates depending on light that will

pass the slit plate holes, and the digital pulse signal is output. ECM will use the signal to figure the

steering wheel speed and angle.

[Output of Lateral G - 90 left] [Output of Lateral G - 90 right]

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Operation

There is a hall plate between the photo-controller LED and the photo transistor. As the hole plate

rotates with steering wheel rotation, electrical signal will be generated depending on whether the

LED light passes through the plate to the photo-transistor or not. The signal is the steering wheel

operation angular velocity and used to detect the steering wheel turning direction.

Hi-

can

STN

Application

- Location: Inside steering wheel

- Calculate the steering amount and direction

- 3 Input Signals (ST 1, ST 2, ST N)

- ST N detects the neutral position of steering wheel

Specification

- Sensor type : Photo interrupt type

- Sensor output type : Open Collector Type- Output pulse quantity :45pulse (Pulse cycle 8)

- Duty ratio : 5010%

- Phase difference of outputs : 2.0 0.6

- Supply voltage :IGN1(9~16V)

- Output voltage :1.3VOL 2.0V,3.0VOH 4.1V

- Maximum rotational velocity : 1,500/s

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data

PRESSURE SENSOR

ST1

ST2

[Steering sensor output, ST1/ST2]

ST1

ST

[Steering sensor output, ST1/STN]

[When the sensor is open]

Application

Sense the drivers braking intentions(braking while an ESP intervention is in progress)

Control the precharging pressure

Design

The sensor consists of two ceramic disks, one of which

is stationary and the other movable. The distance

between these disks changes when pressure is applied.

Installation

[Current data when the sensor is open]

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Function

The pressure sensors operate on the principle of changing capacitance.

The distance (s) between the disks and, thus, the capacitance changes when pressure is appliedto the movable disk by a braking intervention.

The characteristic of the sensor is linearized.

The fluid displacement of the sensor is negligible.

Max. measurable pressure: 170 bar

ss

s1s1

tttt

4.754.754.754.75

0.250.250.250.25

Output](V)Output](V)Output](V)Output](V) Upper fault areaUpper fault areaUpper fault areaUpper fault area

lower fault arealower fault arealower fault arealower fault area

zero pointzero pointzero pointzero point

5.05.05.05.0

0.00.00.00.0

0.50.50.50.5

tttt

4.754.754.754.75

0.250.250.250.25

Output](V)Output](V)Output](V)Output](V) Upper fault areaUpper fault areaUpper fault areaUpper fault area

lower fault arealower fault arealower fault arealower fault area

zero pointzero pointzero pointzero point

5.05.05.05.0

0.00.00.00.0

0.50.50.50.5

[Pressure sensor characteristics]

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ESP SWITCH

The ESP switch deactivates the ESP and TCS

functions. The ESP switch is located on the dash

board of driver side. The system is generally

active after each new start and is only deactivatedby actuating the ESP switch.

This facilitates

- rocking to free the vehicle in deep snow or loose surface material

- driving with snow chains

- operation of the vehicle on a brake test bench

The ABS function is fully maintained.

With the ESP switch, the ESP system can only be deactivated when the vehicle is stationary or

traveling at low speed. The system cannot be deactivated while an ESP intervention is in progress.

8. OUTPUTS

WARNING LAMP CONTROL

a

b

cd

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a) EBD warning lamp control

The active EBD warning lamp module indicates the self-test and failure status of the EBD.

However, in case the Parking Brake Switch is turned on, the EBD warning lamp is always turned

on regardless of EBD functions.

The EBD warning lamp shall be on:

- During the initialization phase after IGN ON. (continuously 3 seconds)

- When the Parking Brake Switch is ON or brake fluid level is low

- When the EBD function is out of order

- During diagnostic mode

- When the ECU Connector is seperated from ECU.

b) ABS warning lamp control

The active ABS warning lamp module indicates the self-test and failure status of the ABS.

The ABS warning lamp shall be on:


- In the event of inhibition of ABS functions by failure


- When the ECU Connector is seperated from ECU.

c) TCS/ESP OFF warning lamp control

The TCS/ ESP warning lamp indicates the self-test and failure status of the TCS/ESP. The TCS/

ESP warning lamp is turned on under the following conditions:

- Ring the initialization phase after IGN ON. (continuously 3 seconds)

- In the event of inhibition of TCS/ESP functions by failure

- When driver turns off the TCS/ESP function by on/off switch

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d) TCS/ESP function lamp control

The TCS/ESP function lamp indicates the self-test and operating status of the TCS/ESP. The ESP

warning lamp lights up briefly when the ignition is turned on and is extinguished as soon as the

peripherals have been checked. During an ESP/TCS control cycle, the ESP function lamp flashes

to show the driver that the system is active and that the vehicle is at the limit of its physical

capabilities. Detection of the fault in the ESP system causes the ESP warning lamp to light up

and remain on. The ESP system is then inactive, the ABS function is fully maintained.

The TCS/ ESP Function lamp operates under the following conditions :


- When the TCS/ESP control is operating. (Blinking - 2Hz)

9. DIAGNOSIS & FAILSAFE

WHEEL SENSOR CHECK FLOW

0 10 20 30 40 50 kph

Sensor H/W

Air-gap Check Air-gap Check(10kph or more)

Speed Jump Check

Wrong Exciter Check

7

Min. ABS operating speed

(7kph)

25

Speed Jump Check

(40g, 10km/h for 7ms)

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MOTOR/SOLENOID CHECK

SAFETY CONCEPT OF THE ESP CONTROL UNIT

In an emergency, it is vital that all ESP components function with absolute reliability. For this

reason, various safety options must be available which guarantee the function of the system. The

0 12k h

Initial check(3sec)

Sol coil open/short to GND, Short to battery ,Fuse

open: Error after 56msec

Fuse open, Motor short to GND, Motor Open: Error

after 200msec

Motor lock check :

Motor voltage check for 84msec after Motor

PWM operation

Motor short to battery: Error after 49msec

Motor Relay Open: Error after 49msec

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most important of these safety options are:

self-test of the electronic control unit

peripheral test of the connected assemblies

SAFETY AND MONITORING SYSTEM

Turning on the ignition activates a self-test of the electronic control unit. After staring, all electric

connections are monitored continuously.

During the trip, the solenoid valves are checked at regular intervals by means of passive test

pulses. In addition, all sensor signals are monitored continuously. The separation of brake circuits

enables the ABS function to be maintained if one brake circuit should fail. This means that the

driving stability of the vehicle is maintained during critical braking maneuvers.

For workshop diagnosis, all faults detected are stored in a nonvolatile memory in the ESP control

unit for retrieval in the workshop location.

SYSTEM MONITORING

The following items are controlled by the ECU:

12 valves

ABS pump

ABS/ESP warning lamps

The following items are monitored by the ECU:

Electronic control unit (include pump and valves)

Wheel speed sensors

Yaw rate sensor

Lateral acceleration sensor

G sensor (for ABS of 4WD vehicle)

Pressure sensor

Onboard voltage CAN bus communication

The warning lamps, the brake light switch and the ESP on/off switch are not monitored.

DTC LIST

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INPUT & OUTPUT SPECIFICATION

EBD ABS TCS/ESP

C1101 Battery voltage high O O O

C1102 Battery voltage low X/O1) O OC1112 Sensor power - failure X X O IGN OFF/ON

C1200 Wheel speed sensor front-LH open/short X/O2) O O

C1201 Wheel speed sensor front-LH range/performance X/O O O

C1202 Wheel speed sensor front-LH invalid/no signal X/O O O

C1203 Wheel speed sensor front-RH open/short X/O O O

C1204 Wheel speed sensor front-RH range/performance X/O O O

C1205 Wheel speed sensor front-RH invalid/no signal X/O O O

C1206 Wheel speed sensor rear-LH open/short X/O O O

C1207 Wheel speed sensor rear-LH range/performance X/O O O

C1208 Wheel speed sensor rear-LH invalid/no signal X/O O O

C1209 Wheel speed sensor rear-RH open/short X/O O O

C1210 Wheel speed sensor rear-RH range/performance X/O O O

C1211 Wheel speed sensor rear-RH invalid/no signal X/O O O

C1235 Pressure sensor(primary) electrical X X O IGN OFF/ON

C1237 Pressure sensor other X X O IGN OFF/ON

C1259 Steering angle sensor electrical X X O IGN OFF/ON

C1260 Steering angle sensor signal X X O IGN OFF/ON

C1274 G sensor electrical X O O IGN OFF/ON

C1275 G sensor signal X O OIGN OFF/ON,

VREF 10km/h

C1282 Yaw rate & lateral G sensor electrical X X O IGN OFF/ON

C1283 Yaw rate & lateral G sensor signal X X O IGN OFF/ON

C2112 Valve relay error O O O IGN OFF/ON

C2227 Excessive temperature of brake disc X X O Cool down

C2380 ABS/TCS/ESP valve error O O O IGN OFF/ON

C2402 Motor electrical X O O IGN OFF/ON

C1503 TCS switch error X X O IGN OFF/ON

C1513 Brake switch error X X O IGN OFF/ONC1604 ECU hardware error O O O IGN OFF/ON

C1605 CAN hardware error X X O IGN OFF/ON

C1611 CAN time-out EMS X X O IGN OFF/ON

C1612 CAN time-out TCU X X O IGN OFF/ON

C1613 CAN wrong message X X O IGN OFF/ON

C1616 CAN bus off X X O IGN OFF/ON

IGN OFF/ON,

VREF 10km/h

Return to

normal voltage

WARNING LAMP RESET

CONDITIONDTC TOUBLE DESCRIPTION

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PIN NAME DESCRIPTION

Over voltage range: 16.50.5V < V

Operating voltage range:

9.50.5V < V < 16.50.5V

Low voltage range:

7.00.5V < V < 9.50.5V

Max. current: I < 300mA

Max leakage current: I < 0.8mA


9.50.5V < V < 16.50.5V

Max current : I < 30A ABS/TCS only

Max current : I < 40A ESP only


9.50.5V < V < 16.50.5V

Rush current : I < 100A

Max current : I < 30A

Max leakage current : I < 0.2mA

Max. current: I < 30A In ABS/TCS control ABS/TCS only

Max. current: I < 40A In ESP control ESP only

Rush current : I < 100A

Max current : I < 30A

YAW_SEN_GNDYAW & LATERAL G

SENSOR GROUNDRated current : I65mA ESP only

MP_SEN_GNDMASTER PRESSURE


SAS_GNDSTEERING ANGLE


Max Output current :

I < 10mA

Max Output voltage :

4.9V V 5.1V

Max Output current : I < 65mA

Max Output voltage : 4.9V V 5.1V

CONNECTOR TERMINALSPECIFICATION NOTE SYSTEM

IGN IGNITION1 (+) Common

BAT1POS. BATTERY.

(SOLENOID)

Common

BAT2POS. BATTERY.

(MOTOR)Common

GND GROUND

Rated current : I300mA Common

PGNDPUMP MOTOR

GROUND

In ABS/TCS/ESP

controlCommon

MP_POWERMASTER PRESSURE

SENSOR POWERESP only

YAW_POWERYAW SENSOR

POWERESP only

Rush current

Continuous current

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PIN NAME DESCRIPTION

Sensor Input Voltage: 0V V 5V

Zero offset Voltage: 0.5V 0.15V

Input current :Max 2 Ma


Zero offset Voltage : 2.5 0.1V


Zero offset Voltage : 2.5 0.1V

ABS ACTIVE ABS ACTIVE SIGNAL Max. current : I < 200mA ABS 4WD only

G SENSOR G SENSOR SIGNAL Input Voltage : 0 V 5.0V

G SENSOR_GND G SENSOR GROUND Rated current : I 10mA

YAW_CBIT SELF TEST Output Voltage: 0V V 5V ESP only

Input voltage

VIL < 0.3 VIGN [V]

VIH > 0.7 VIGN [V]

Output voltage :

VOL < 0.2 VIGN [V]

VOH > 0.8 VIGN [V]

DIAGDIAGNOSIS

INPUT/OUTPUTCommon

CONNECTOR TERMINAL

4WD only

YAW SENSORYAW SENSOR

SIGNALESP only

MP SENSOR ESP only

LATERAL G ESP only

MASTER PRESSURE

SENSOR SIGNAL

LATERAL G SENSOR

SIGNAL

SYSTEMSPECIFICATION NOTE

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WIRING DIAGRAM

1) ABS

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2) TCS

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3) ESP

ESP_JM

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