Content .. 1080 1081 1082 1083 ..

Opel Frontera UBS. Manual - part 1082

5A–1

BRAKE CONTROL SYSTEM

BRAKES

CONTENTS

Brake Control System

. . . . . . . . . . . . . . . . . . . .

Anti–lock Brake System

. . . . . . . . . . . . . . . . . .

Power–Assisted Brake System

. . . . . . . . . . . .

Parking Brakes

. . . . . . . . . . . . . . . . . . . . . . . . .

BRAKE CONTROL SYSTEM

CONTENTS

Service Precaution

5A–2

. . . . . . . . . . . . . . . . . . . . . .

General Description

5A–3

. . . . . . . . . . . . . . . . . . . . .

System Components

5A–3

. . . . . . . . . . . . . . . . . . .

Electronic Hydraulic Control Unit (EHCU)

5A–3

ABS Warning Light

5A–4

. . . . . . . . . . . . . . . . . . . .

Wheel Speed Sensor

5A–4

. . . . . . . . . . . . . . . . . .

G-Sensor

5A–4

. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Normal and Anti-lock Braking

5A–4

. . . . . . . . . . .

Brake Pedal Travel

5A–4

. . . . . . . . . . . . . . . . . . . .

Acronyms and Abbreviations

5A–4

. . . . . . . . . . . .

General Diagnosis

5A–5

. . . . . . . . . . . . . . . . . . . . . . .

General Information

5A–5

. . . . . . . . . . . . . . . . . . . .

ABS Service Precautions

5A–5

. . . . . . . . . . . . . . .

Computer System Service Precautions

5A–5

. . .

General Service Precautions

5A–5

. . . . . . . . . . . .

Note on Intermittents

5A–5

. . . . . . . . . . . . . . . . . . .

Test Driving ABS Complaint Vehicles

5A–6

. . . . .

“ABS” Warning Light

5A–6

. . . . . . . . . . . . . . . . . . .

Normal Operation

5A–6

. . . . . . . . . . . . . . . . . . . . .

Basic Diagnostic Flow Chart

5A–6

. . . . . . . . . . . .

Basic Inspection Procedure

5A–7

. . . . . . . . . . . . .

Tech 2 Scan Tool

5A–8

. . . . . . . . . . . . . . . . . . . . . .

Getting Started

5A–9

. . . . . . . . . . . . . . . . . . . . . . . .

Operating Procedure

5A–10

. . . . . . . . . . . . . . . . . . .

Data List

5A–11

. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

EHCU Connector Pin-out Checks

5A–12

. . . . . . . .

Circuit Diagram (LHD model / 6VD1 and
4JG2)

5A–13

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Circuit Diagram (LHD model / 4JG2)

5A–14

. . . . .

Circuit Diagram (LHD model / 4JG2)

5A–15

. . . . .

Circuit Diagram (LHD model / 6VD1)

5A–16

. . . . .

Circuit Diagram (LHD model / 6VD1)

5A–17

. . . . .

Connector List (LHD model)

5A–18

. . . . . . . . . . . .

Part Location (LHD model)

5A–20

. . . . . . . . . . . . . .

Circuit Diagram (RHD model / 6VD1 and
4JG2)

5A–21

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Circuit Diagram (RHD model / 4JG2)

5A–22

. . . . .

Circuit Diagram (RHD model / 4JG2)

5A–23

. . . . .

Circuit Diagram (RHD model / 6VD1)

5A–24

. . . . .

Circuit Diagram (RHD model / 6VD1)

5A–25

. . . . .

Circuit Diagram (RHD model / 6VE1 and
4JX1)

5A–26

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Circuit Diagram (RHD model / 4JX1)

5A–27

. . . . .

Circuit Diagram (RHD model / 4JX1)

5A–28

. . . . .

Circuit Diagram (RHD model / 6VE1)

5A–29

. . . . .

Circuit Diagram (RHD model / 6VE1)

5A–30

. . . . .

Connector List (RHD model)

5A–31

. . . . . . . . . . . .

Part Location (RHD model)

5A–34

. . . . . . . . . . . . .

Symptom Diagnosis

5A–35

. . . . . . . . . . . . . . . . . . . . .

Chart A–1 ABS Works Frequently But
Vehicle Does Not Decelerate

5A–35

. . . . . . . . . . .

Chart TA-1 ABS Works Frequently But
Vehicle Does Not Decelerate (Use
TECH 2)

5A–36

. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Chart A-2 Uneven Braking Occurs While
ABS Works

5A–36

. . . . . . . . . . . . . . . . . . . . . . . . . . .

Chart A-3, TA-3 The Wheels Are Locked

5A–36

Chart A-4 Brake Pedal Feed Is Abnormal

5A–37

Chart A-5, TA-5 Braking Sound (From
EHCU) Is Heard While Not Braking

5A–38

. . . . . .

Diagnostic Trouble Codes

5A–39

. . . . . . . . . . . . . . . .

Diagnosis By “ABS” Warning Light
Illumination Pattern

5A–40

. . . . . . . . . . . . . . . . . . . . .

Diagnostic Trouble Codes (DTCs)

5A–40

. . . . . . .

Chart B-1 With the key in the ON position
(Before starting the engine). Warning light
(W/L) is not activated.

5A–43

. . . . . . . . . . . . . . . . .

Chart B-2 EHCU Abnormality (DTC 14)

5A–43

. . .

Chart B-3 Power Voltage Drop (DTC 15)

5A–44

. .

Chart B-4 CLASS-2 Communication Line
Abnormality (DTC 16)

5A–44

. . . . . . . . . . . . . . . . .

Chart B-5 G-Sensor Circuit (DTC 21)

5A–45

. . . . .

Chart B-6 Abnormal Transmission Input
(DTC 23)

5A–46

. . . . . . . . . . . . . . . . . . . . . . . . . . . .

Chart B-7 Transfer Monitor (DTC 24)

5A–47

. . . . .

Chart B-8 EHCU Pump Motor And Motor
Relay Circuit (DTC 32)

5A–47

. . . . . . . . . . . . . . . . .

Chart B-9 EHCU Pump Valve And Valve
Relay Circuit (DTC 35)

5A–47

. . . . . . . . . . . . . . . . .

Chart B-10 FL Isolation Solenoid Valve
Abnormality (DTC 41)

5A–48

. . . . . . . . . . . . . . . . .

Chart B-11 FL Dump Solenoid Valve
Abnormality (DTC 42)

5A–48

. . . . . . . . . . . . . . . . .

Chart B-12 FR Isolation Solenoid Valve
Abnormality (DTC 43)

5A–48

. . . . . . . . . . . . . . . . .

Chart B-13 FR Dump Solenoid Valve
Abnormality (DTC 44)

5A–49

. . . . . . . . . . . . . . . . .

Chart B-14 Rear Isolation Solenoid Valve
Abnormality (DTC 45)

5A–49

. . . . . . . . . . . . . . . . .

Chart B-15 Rear Dump Solenoid Valve
Abnormality (DTC 46)

5A–49

. . . . . . . . . . . . . . . . .

SECTION

5A–2

BRAKE CONTROL SYSTEM

Chart B-16 FL Speed Sensor Disconnection
(DTC 51)

5A–50

. . . . . . . . . . . . . . . . . . . . . . . . . . . .

Chart B-17 FR Speed Sensor Disconnection
(DTC 52)

5A–50

. . . . . . . . . . . . . . . . . . . . . . . . . . . .

Chart B-18 RL Speed Sensor Disconnection
(DTC 53)

5A–51

. . . . . . . . . . . . . . . . . . . . . . . . . . . .

Chart B-19 RR Speed Sensor Disconnection
(DTC 54)

5A–51

. . . . . . . . . . . . . . . . . . . . . . . . . . . .

Chart B-20 FL Speed Sensor Short Circuit
(DTC 61)

5A–52

. . . . . . . . . . . . . . . . . . . . . . . . . . . .

Chart B-21 FR Speed Sensor Short Circuit
(DTC 62)

5A–53

. . . . . . . . . . . . . . . . . . . . . . . . . . . .

Chart B-22 RL Speed Sensor Short Circuit
(DTC 63)

5A–54

. . . . . . . . . . . . . . . . . . . . . . . . . . . .

Chart B-23 RR Speed Sensor Short Circuit
(DTC 64)

5A–55

. . . . . . . . . . . . . . . . . . . . . . . . . . . .

Chart B-24 Sensor Signal Input Abnormality
(DTC 65)

5A–56

. . . . . . . . . . . . . . . . . . . . . . . . . . . .

Sensor Signal Abnormality Criteria using
TECH 2

5A–56

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Unit Inspection Procedure

5A–57

. . . . . . . . . . . . . . . .

Chart C-1-1 FL Sensor Output Inspection
Procedure

5A–57

. . . . . . . . . . . . . . . . . . . . . . . . . . .

Chart C-1-2 FR Sensor Output Inspection
Procedure

5A–58

. . . . . . . . . . . . . . . . . . . . . . . . . . .

Chart C-1-3 RL Sensor Output Inspection
Procedure

5A–58

. . . . . . . . . . . . . . . . . . . . . . . . . . .

Chart C-1-4 RR Sensor Output Inspection
Procedure

5A–59

. . . . . . . . . . . . . . . . . . . . . . . . . . .

Chart TC-1 Sensor Output Inspection
Procedure (Use TECH 2)

5A–59

. . . . . . . . . . . . . .

Chart C-2 Transmission Input Inspection
Procedure

5A–60

. . . . . . . . . . . . . . . . . . . . . . . . . . .

Chart TC-2 Transmission Input Inspection
Procedure (Use TECH 2)

5A–61

. . . . . . . . . . . . . .

Special Tools

5A–62

. . . . . . . . . . . . . . . . . . . . . . . . . . .

Service Precaution

WARNING: IF SO EQUIPPED WITH A
SUPPLEMENTAL RESTRAINT SYSTEM (SRS),
REFER TO THE SRS COMPONENT AND WIRING
LOCATION VIEW IN ORDER TO DETERMINE
WHETHER YOU ARE PERFORMING SERVICE ON OR
NEAR THE SRS COMPONENTS OR THE SRS
WIRING. WHEN YOU ARE PERFORMING SERVICE
ON OR NEAR THE SRS COMPONENTS OR THE SRS
WIRING, REFER TO THE SRS SERVICE
INFORMATION. FAILURE TO FOLLOW WARNINGS
COULD RESULT IN POSSIBLE AIR BAG
DEPLOYMENT, PERSONAL INJURY, OR
OTHERWISE UNNEEDED SRS SYSTEM REPAIRS.

CAUTION: Always use the correct fastener in the
proper location. When you replace a fastener, use
ONLY the exact part number for that application.
ISUZU will call out those fasteners that require a
replacement after removal. ISUZU will also call out
the fasteners that require thread lockers or thread
sealant. UNLESS OTHERWISE SPECIFIED, do not
use supplemental coatings (Paints, greases, or other
corrosion inhibitors) on threaded fasteners or
fastener joint interfaces. Generally, such coatings
adversely affect the fastener torque and the joint
clamping force, and may damage the fastener. When
you install fasteners, use the correct tightening
sequence and specifications. Following these
instructions can help you avoid damage to parts and
systems.

5A–3

BRAKE CONTROL SYSTEM

General Description

The Anti-lock Brake System (ABS) works on all four
wheels. A combination of wheel speed sensor and
Electronic Hydraulic Control Unit (EHCU) can determine
when a wheel is about to stop turning and adjust brake
pressure to maintain best braking.

This system helps the driver maintain greater control of
the vehicle under heavy braking conditions.

C05RW027

Legend

(1) With P&B Valve Model
(2) With LSPV Model
(3) Electronic Hydraulic Control Unit (EHCU)
(4) Front Wheel Speed Sensor
(5) Rear Wheel Speed Sensor

(6) G-Sensor
(7) Proportioning and Bypass (P&B) Valve
(8) Load Sensing Proportioning Valve (LSPV)
(9) Electronic Line

(10) Hydraulic Line

System Components

Electronic Hydraulic Control Unit (EHCU), four Wheel
Speed Sensors, Warning Light, and G-sensor.

Electronic Hydraulic Control Unit (EHCU)

The EHCU consists of ABS control circuits, fault detector,
and a fail-safe. It drives the hydraulic unit according to the
signal from each sensor, cancelling ABS to return to

5A–4

BRAKE CONTROL SYSTEM

normal braking when a malfunction has occurred in the
ABS.
The EHCU has a self-diagnosing function which can
indicate faulty circuits during diagnosis.
The EHCU is mounted on the engine compartment front
right side. It consists of a Motor, Plunger Pump, Solenoid
Valves and Check Valve.
On the outside, the relay box containing a motor relay and
a valve relay is installed.
Solenoid Valves: Reduces or holds the caliper fluid
pressure for each front disc brake or both rear disc brakes
according to the signal sent from the EHCU.
Reservoir: Temporarily holds the brake fluid that returns
from the front and rear disc brake caliper so that pressure
of front disc brake caliper can be reduced smoothly.
Plunger Pump: Feeds the brake fluid held in the reservoir
to the master cylinder.
Motor: Drives the pump according to the signal from
EHCU.
Check Valve: Controls the brake fluid flow.

ABS Warning Light

821RW033

Vehicles equipped with the Anti-lock Brake System have
an amber “ABS” warning light in the instrument panel.
The “ABS” warning light will illuminate if a malfunction in
the Anti-lock Brake System is detected by the Electronic
Hydraulic Control Unit (EHCU). In case of an electronic
malfunction, the EHCU will turn “ON” the “ABS” warning
light and disable the Anti-lock braking function.
The “ABS” light will turn “ON” for approximately three
seconds after the ignition switch is to the “ON” position.
If the “ABS” light stays “ON” after the ignition switch is the
“ON” position, or comes “ON” and stays “ON” while
driving, the Anti-lock Brake System should be inspected
for a malfunction according to the diagnosis procedure.

Wheel Speed Sensor

It consists of a sensor and a rotor. The sensor is attached
to the knuckle on the front wheels and to the axle shaft
bearing holder on the rear wheels.
The rotor is press-fit in the axle shaft.

The flux generated from electrodes magnetized by a
magnet in the sensor varies due to rotation of the rotor,
and the electromagnetic induction generates alternating
voltage in the coil. This voltage draws a “sine curve” with
the frequency proportional to rotor speed and it allows
detection of wheel speed.

G-Sensor

The G-sensor installed inside the center console detects
the vehicle deceleration speed and sends a signal to the
EHCU. In 4WD operation, all four wheels may be
decelerated in almost the same phase, since all wheels
are connected mechanically.
This tendency is noticeable particularly on roads with low
friction coefficient, and the ABS control is adversely
affected.
The G-sensor judges whether the friction coefficient of
road surface is low or high, and changes the EHCU’s
operating system to ensure ABS control.

Normal and Anti-lock Braking

Under normal driving conditions, the Anti-lock Brake
System functions the same as a standard power assisted
brake system. However, with the detection of wheel
lock-up, a slight bump or kick-back will be felt in the brake
pedal. This pedal “bump” will be followed by a series of
short pedal pulsations which occurs in rapid succession.
The brake pedal pulsation will continue until there is no
longer a need for the anti-lock function or until the vehicle
is stopped. A slight ticking or popping noise may be heard
during brake applications when the Anti-lock features is
being used.
When the Anti-lock feature is being used, the brake pedal
may rise even as the brakes are being applied. This is
also normal. Maintaining a constant force on the pedal
will provide the shortest stopping distance.

Brake Pedal Travel

Vehicles equipped with the Anti-lock Brake System may
be stopped by applying normal force to the brake pedal.
Although there is no need to push the pedal beyond the
point where it stops or holds the vehicle, by applying more
force the pedal will continue to travel toward the floor.
This extra brake pedal travel is normal.

Acronyms and Abbreviations

Several acronyms and abbreviations are commonly used
throughout this section:

ABS
Anti-lock Brake System

CKT
Circuit

DLC
Data Link Connector

EHCU
Electronic Hydraulic Control Unit

FL
Front Left

Content .. 1080 1081 1082 1083 ..