JAC HFC4DA1-2C engine. Instruction — part 35
BR
BR
BR
BR Brake
Brake
Brake
Brake System
System
System
System
- 67-
Removal/Installation
Removal/Installation
Removal/Installation
Removal/Installation
5.
Remove the seal ring between generator and
vacuum pump.
Installation
1.
Reinstall the seal ring between generator and
vacuum pump.
2.
Reinstall the vacuum booster.
3.
Reinstall the oil inlet pipe and the oil return pipe
onto the pump.
4.
Connect the vacuum pipe onto the pump.
5.
Connect the negative cable of battery.
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BR
BR
BR
BR Brake
Brake
Brake
Brake System
System
System
System
- 68 -
Removal/installation
Removal/installation
Removal/installation
Removal/installation of
of
of
of vacuum
vacuum
vacuum
vacuum booster
booster
booster
booster
Caution:
Caution:
Caution:
Caution:
Don’t the make the brake fluid splashing onto the
paint surface. In case of any, please wash the
surface with clean water immediately.
Removal
1.
Disconnect the negative cable of battery.
2.
Disconnect the harness connector of the brake fluid
level warning switch.
3.
Disconnect the brake fluid circuit.
Note:
Note:
Note:
Note:
Plug the pipe orifice to avoid contamination by
dirt.
4.
Remove the brake line from the master cylinder.
5.
Remove the vacuum booster hose connector
carefully.
6.
Remove the clevis pin and spring clip from the
vacuum booster control rod of brake pedal.
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BR
BR
BR
BR Brake
Brake
Brake
Brake System
System
System
System
- 69-
Removal/Installation
Removal/Installation
Removal/Installation
Removal/Installation
7.
Remove the brake switch.
�
Remove the harness connector.
8.
Remove the booster and master cylinder assembly.
9.
Separate the booster from the master cylinder.
Installation
1.
Install the vacuum booster.
2.
Install the booster control rod onto the brake pedal.
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BR
BR
BR
BR Brake
Brake
Brake
Brake System
System
System
System
- 70 -
Removal/Installation
Removal/Installation
Removal/Installation
Removal/Installation
3.
Reinstall and debug the brake switch.
4.
Reinstall the master cylinder onto the booster.
Ensure proper position and clean joint surface for
sealing washer of vacuum pump.
5.
Reconnect the brake line.
6.
Reconnect the brake line with the master cylinder.
7.
Install the vacuum booster pipe connector.
8.
Connect the brake fluid level warning sensor
connector.
9.
Connect the negative cable of battery.
10. Bleed air out of brake system in accordance with
specification.
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BR
BR
BR
BR Brake
Brake
Brake
Brake System
System
System
System
- 71-
Air
Air
Air
Air bleeding
bleeding
bleeding
bleeding for
for
for
for brake
brake
brake
brake system
system
system
system
Caution:
Caution:
Caution:
Caution:
Don’t the make the brake fluid splashing onto the
paint surface. In case of any, please wash the
surface with clean water immediately.
1.
Disconnect the ground wire of battery.
2.
Have the vehicle lifted.
3.
Connect the oil drain pipe to the air vent of four
wheels.
4.
Loosen the bleeder screw.
Note:
Note:
Note:
Note:
Keep the brake fluid reservoir cap clean.
5.
Open the brake fluid reservoir cap.
6.
Bleed air out of the front circuit.
Fill the fluid reservoir with brake fluid with the
brake pedal fully depressed, release the brake pedal
immediately and then hold the brake pedal
depressed. Loosen the bleeder screw of wheel
cylinder to bleed air out of system. Perform air
bleeding for wheels in the order of left rear, right
front, right rear and left front. Tighten the bleeder
screw once no air bubble is observed.
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ABS
ABS
ABS
ABS Anti-lock
Anti-lock
Anti-lock
Anti-lock Brake
Brake
Brake
Brake System
System
System
System
- 73 -
Anti-lock Brake System (ABS)
Applied models: SUNRAY products manufactured by JAC
Subject
Page
Instruction
Instruction
Instruction
Instruction and
and
and
and Operation
Operation
Operation
Operation
ABS system. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
Diagnosis
Diagnosis
Diagnosis
Diagnosis and
and
and
and Testing
Testing
Testing
Testing
ABS system. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
Operating principle. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 79
Inspection and confirmation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .81
Fault Symptom Table. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... 85
Removal/Installation
Removal/Installation
Removal/Installation
Removal/Installation
ABS system. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..101
Wheel speed sensor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
-------------------------------------------------------------------------------------------------------------------------------------------------------------
ABS
ABS
ABS
ABS Anti-lock
Anti-lock
Anti-lock
Anti-lock Brake
Brake
Brake
Brake System
System
System
System
- 74 -
Instruction
Instruction
Instruction
Instruction and
and
and
and Operation
Operation
Operation
Operation
Anti-lock
Anti-lock
Anti-lock
Anti-lock brake
brake
brake
brake system
system
system
system (ABS)
(ABS)
(ABS)
(ABS)
BOCSH 8 ABS is adopted for JAC multifunctional commercial vehicles.
ABS Hydraulic Assembly
-------------------------------------------------------------------------------------------------------------------------------------------------------------
ABS
ABS
ABS
ABS Anti-lock
Anti-lock
Anti-lock
Anti-lock Brake
Brake
Brake
Brake System
System
System
System
- 75 -
Instruction
Instruction
Instruction
Instruction and
and
and
and Operation
Operation
Operation
Operation
Operating
Operating
Operating
Operating principle
principle
principle
principle
Connection
Connection
Connection
Connection Diagram
Diagram
Diagram
Diagram of
of
of
of ABS
ABS
ABS
ABS Brake
Brake
Brake
Brake Line
Line
Line
Line (Diagonal Layout)
-------------------------------------------------------------------------------------------------------------------------------------------------------------
ABS
ABS
ABS
ABS Anti-lock
Anti-lock
Anti-lock
Anti-lock Brake
Brake
Brake
Brake System
System
System
System
- 76 -
Instruction
Instruction
Instruction
Instruction and
and
and
and Operation
Operation
Operation
Operation
Precautions
Precautions
Precautions
Precautions for
for
for
for ABS
ABS
ABS
ABS system
system
system
system diagnosis
diagnosis
diagnosis
diagnosis
As ABS is a safety related component, the following
precautions should be observed in addition to general
safety and preventive measures that should be taken in
the course of maintenance and diagnosis.
1.
Maintenance for ABS system should be conducted
by specially trained technicians that mastering the
maintenance
skills
and
only
genuine
parts
manufactured by the original manufacturers should
be applied for replacement.
2.
Before conducting diagnosis over ABS system, the
conventional
brake
system
should
operate
normally.
3.
Before and during travelling, ABS ECU shall
perform continuously monitoring over ABS related
electrical components to see if they can operate
normally.
4.
ABS and EBD lamps shall be lit when the ignition
switch is turned on and go out in several seconds
based on no fault existed in system.
5.
The following two conditions indicate that there is
fault detected in the system:
① The warning lamp keeps on after the ignition
switch is turned on;
② The warning lamp doesn’t go out after it is
turned on during travelling.
Under those conditions, the driver can still
apply conventional brake but should minimize
the applied braking force to avoid wheel
locking. Therefore, please be attentive to drive
carefully after the warning lamp is lit. Please go
to the service shop for maintenance of ABS
system as soon as possible in order to avoid
occurrence of more faults and traffic accidents.
6.
ABS hydraulic governor with ECU consists of the
following parts:
① ABS ECU: Including reflux pump motor relay
and solenoid valve relay;
② Solenoid valves (8): Including 4 oil inlet valves
and 4 oil outlet valves;
③ Reflux pump and pressure accumulator;
④ Others: Motor, bolts and so on. They can only
be replaced as a whole instead of being
removed
for
overhaul
or
partly/separately
replaced. BOSCH Company won’t provide
separate spare parts, won’t provide maintenance
warranty for the disassembled ABS with
hydraulic controller, as well as won’t bear any
responsibility for consequences
caused by
removal overhaul or part/separate replacement.
7.
Connectors for ABS ECU:
① The ignition switch must be turned off before
the removal of connectors for ABS ECU;
② Keep the connectors for ABS ECU dry and
clean without any foreign matter;
③ The connectors for ABS ECU must be
installed in position with bottom parallel to
the base;
④ The connectors for ABS ECU must be
installed in position with lateral part vertical
to the base.
8.
ABS hydraulic governor with ECU should be
grounded properly. If not, water and moisture shall
permeate into connectors of ABS ECU via pore
path of harness under the capillary (syphon) effect,
leading to failure.
9.
Please ensure ABS brake line properly connected,
because ABS ECU is unable to diagnose whether
the brake line is properly connected or not and to
realize failure protection. Wrong connection may
possibly lead to severe accidents.
�
MC1: Connected with brake line 1 of brake
master cylinder;
�
MC2: Connected with brake line 2 of brake
master cylinder
�
FL: Connected with brake line of left front
brake wheel cylinder;
�
FR: Connected with brake line of right front
brake wheel cylinder;
�
RL: Connected with brake line of left rear
brake wheel cylinder;
�
RR: Connected with brake line of right rear
brake wheel cylinder.
10. Ensure each wheel speed sensor wiring properly
connected.
-------------------------------------------------------------------------------------------------------------------------------------------------------------
ABS
ABS
ABS
ABS Anti-lock
Anti-lock
Anti-lock
Anti-lock Brake
Brake
Brake
Brake System
System
System
System
- 77 -
Instruction
Instruction
Instruction
Instruction and
and
and
and Operation
Operation
Operation
Operation
Fault
Fault
Fault
Fault diagnosis
diagnosis
diagnosis
diagnosis procedures
procedures
procedures
procedures for
for
for
for ABS
ABS
ABS
ABS with
with
with
with EBD
EBD
EBD
EBD
S/N
Operation
1
Drive the vehicle into repair shop.
Go to the next step.
2
Customer problem analysis
Go to the next step.
3
Read diagnostic trouble code (DTC).
With DTC
Go to Step 4
No DTC
Go to Step 9
4
Record DTC and clear fault memory.
Go to the next step.
5
Verify and reproduce fault: Simulation of fault occurrence status.
Read DTC again.
With DTC
Current DTC. Go to Step 8
No DTC
History DTC. Go to Step 6
6
Is it relevant to fault symptom?
Yes
Intermittent fault. Go to Step 7
No
Eliminated fault. Go to Step 9
7
Perform fault simulation again.
Go to the next step.
8
Perform troubleshooting based on DTC list. Go to Step 10.
Go to the next step.
9
Perform troubleshooting based on fault symptom list.
Go to the next step.
10
Ensure the fault is eliminated.
Go to the next step.
11
Prevention of recurrence.
Go to the next step.
12
End
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ABS
ABS
ABS
ABS Anti-lock
Anti-lock
Anti-lock
Anti-lock Brake
Brake
Brake
Brake System
System
System
System
78
Diagnosis
Diagnosis
Diagnosis
Diagnosis and
and
and
and Testing
Testing
Testing
Testing
Diagnosis
Diagnosis
Diagnosis
Diagnosis
1.
Preliminary inspection
Inspect those easily accessible components that may
lead to ABS system fault. Faults can be determined
quickly through visual and appearance inspection, in no
need of further diagnosis.
(a)
Ensure the vehicle is equipped with wheels and
tires of recommended size. Coaxial tires should be
of the same pattern and tread depth.
(b) Check the hydraulic governor, brake line and
connector for leak.
(c)
Check ABS fuses - 10A, 25A and 40A. Only the
fuses of correct rating should be applied.
(d) Ensure the battery is fully charged.
(e)
Check battery connection for corrosion or terminal
looseness.
(f)
Perform visual and appearance inspection for
electrical components listed below:
①
Check ABS component harnesses and pins for
wrong connection, damage due to clamping or
cutting.
②
Check whether the harnesses are arranged
close to high voltage or heavy current devices,
such as:
�
High voltage ignition component;
�
Motor and generator;
�
Stereo amplifier optional equipped.
IMPORTANT: High voltage or heavy current
devices are likely to make induced noise generated
in circuit interfering normal operation of circuit.
③
Check connectors of ABS system relevant
components for poor connection or check pins
for incomplete insertion into connector shells.
④
ABS
components
are
sensitive
to
electromagnetic interference (EMI). If any
intermittent fault is suspicious, please check
whether
the
optional
equipped
anti-theft
devices, lamps or mobile phones are properly
installed.
(g) ABS is a kind of active safety system, which
mainly functions to maintain vehicle’s steerability
and driving stability in the course of braking and to
minimize the braking distance through obtaining
the maximum deceleration. With the adoption of
ABS for braking, there is little but uniform tire
wear, for adhesion applied between tire and road
surface is realized based on adhesion coefficient
limit. However, ABS is unable to avoid skidding of
vehicle completely if the vehicle speed at turning
exceeds the limit or the vehicle is running at high
speed on slippery road.
(h) ABS sound
When the vehicle is running for about 15Km/h
after the start of engine, there is a short buzz
generated in the engine compartment, which is the
sound of ABS self-checking but not abnormal noise.
Kinds of sound in the course of ABS functioning
include:
�
Operation sound of motor, solenoid valve and
reflux pump inside ABS hydraulic unit;
�
Sound generated from vibration of brake
pedal;
�
Suspension knock sound arisen by braking
during ABS operation.
�
Excessive noise during system self-checking
or ABS functioning may be caused by:
�
Looseness of ABS fixation;
�
Looseness of ABS bracket;
�
Damage or missing of plastic washers on ABS
bracket;
�
Looseness of brake relevant connection or
fixation;
�
Brake
line
connection
direction
nonconforming to delivery status;
�
Air bubbles in brake line.
�
-------------------------------------------------------------------------------------------------------------------------------------------------------------
ABS
ABS
ABS
ABS Anti-lock
Anti-lock
Anti-lock
Anti-lock Brake
Brake
Brake
Brake System
System
System
System
- 79 -
ABS
ABS
ABS
ABS Operating
Operating
Operating
Operating principle
principle
principle
principle::::
ABS shall enter antilock brake mode once wheel
skidding is detected during braking. In the course of
antilock braking, the hydraulic circuit pressure of each
wheel is under control to avoid wheel skidding. Each
wheel is equipped with individual hydraulic line and
valve. ABS is able to reduce, maintain or increase the
hydraulic pressure of each wheel braking. However, it is
unable to increase the hydraulic pressure to a certain
level that exceeds the pressure delivered by the master
cylinder during braking. In the course of antilock
braking, a series of quick vibration of brake pedal can
be felt. The pedal vibration shall appear during antilock
braking and disappear during conventional braking or
after complete stop of vehicle. Operation noise can be
heard due to quick cycle use of solenoid valve. When
antilock braking is applied on dry road, intermittent
sharp noise shall generate right before wheel skidding.
Those noises and pedal vibration under antilock braking
are normal symptoms. Operation of brake pedal during
conventional braking should be the same as that of
vehicle without ABS system. Maintain balance pedal
force can both ensure the vehicle stability and the
shortest stopping distance.
1.
Pressure maintenance
Once wheel skidding is detected, ABS control module
shall close the oil inlet valve and then make the oil
outlet valve in the hydraulic assembly closed to isolate
the system, which can keep the brake pressure stable
and avoid boosting or reducing of hydraulic pressure.
2.
Pressure reducing
Under the pressure maintenance mode, wheel skidding
can still be detected by ABS control module to reduce
the affected wheel pressure. Keep the oil inlet valve
closed and oil outlet valve open. The redundant
fluid/pressure shall be temporarily stored into the
accumulator in hydraulic assembly until the pump motor
is able to return the brake fluid into oil reservoir of
master cylinder.
3.
Pressure boosting
If decrease of wheel skidding is detected by ABS
control module under pressure maintenance or pressure
reducing mode, the ABS control module shall boost the
affected wheel pressure through applying the pressure of
master cylinder. Keep the oil inlet valve open and oil
outlet valve closed. Pressure from master cylinder shall
be partly or fully applied onto wheels.
4.
Operating procedures of ABS
During vehicle running, each wheel speed sensor shall
produce a voltage signal in proportion to wheel speed.
ABS control module shall make judgment based on the
received wheel speed data; if more than one wheels
decelerate rapidly (compared with reference vehicle
speed), it is determined as skidding. ABS control
module shall activate the module as required to control
over the brake pressure of each wheel to achieve
optimization.
Schematic
Schematic
Schematic
Schematic Diagram
Diagram
Diagram
Diagram of
of
of
of ABS
ABS
ABS
ABS Hydraulic
Hydraulic
Hydraulic
Hydraulic System
System
System
System::::
M
1
2
9
RF
LF
RR
LR
10
6
11
12
4
5
3
8
7
Schematic Diagram of ABS Hydraulic System
1. Master cylinder
2. Oil inlet valve (LF)
3. Oil outlet valve (LF)
4. Oil inlet valve (RR)
5. Oil outlet valve
(RR)
6. Damper
7. Oil return pump 8. Accumulator
9. Oil inlet valve (RF)
10. Oil outlet valve (RF)
11. Oil
inlet valve (LR)
12. Oil outlet valve (LR)
-------------------------------------------------------------------------------------------------------------------------------------------------------------
ABS
ABS
ABS
ABS Anti-lock
Anti-lock
Anti-lock
Anti-lock Brake
Brake
Brake
Brake System
System
System
System
- 80 -
Diagnosis
Diagnosis
Diagnosis
Diagnosis and
and
and
and Testing
Testing
Testing
Testing
Diagnosis
Diagnosis
Diagnosis
Diagnosis
Checking instrument warning lamp
(a) Release the parking brake lever.
(b) Check the warning lamp.
With the ignition switch turned on, check if ABS
and EBD warning lamps is lit and then go out in a
few seconds.
Remarks:
�
With the parking brake applied, the EBD
warning lamp shall be lit (details based on
actual conditions).
�
As for some vehicle models, EBD warning
lamp shall be lit if brake fluid level is too low
(details based on actual conditions).
�
In case of abnormal operation of warning
lamps, please perform troubleshooting for
ABS or EBD warning lamp circuit.
S/N
Operation Sequence
EBD Warning
Lamp
ABS Warning
Lamp
1
With the ignition switch turned on, ABS and EBD warning lamps should be lit.
If the system is normal, the warning lamps shall go out in about 3 seconds.
ON
ON
2
The system is normal after self-checking.
OFF
OFF
3
① There is current DTC not removed in ABS.
ABS stops operation but EBD is still operating.
For example: Only one wheel speed sensor failed.
② There are current DTCs of wheel speed sensor and reflux pump in ABS.
With the vehicle speed below 12Km/h, ABS warning lamp is lit but ABS stops operation.
With the vehicle speed no below 12Km/h, ABS warning lamp goes out after no fault is
detected and the current DTC becomes the history DTC.
ON
OFF
4
① Diagnosis on ABS by diagnostic instrument.
With the vehicle speed below 10Km/h, all diagnoses of ABS function normally.
With the vehicle speed over 10Km/h, two lamps go out once the system is detected to be
normal and diagnosis is cut off automatically if the ABS controls normally.
②EBD failure.
Both ABS and EBD stop operation.
For example: Over three wheel speed sensors failed.
ON
ON
5
Too low brake fluid level or unreleased parking brake lever (details based on actual
conditions).
Both ABS and EBD electrical components operate normally.
OFF
ON
-------------------------------------------------------------------------------------------------------------------------------------------------------------
ABS
ABS
ABS
ABS Anti-lock
Anti-lock
Anti-lock
Anti-lock Brake
Brake
Brake
Brake System
System
System
System
- 81 -
Diagnosis
Diagnosis
Diagnosis
Diagnosis and
and
and
and Testing
Testing
Testing
Testing
Detection
Detection
Detection
Detection by
by
by
by diagnostic
diagnostic
diagnostic
diagnostic instrument
instrument
instrument
instrument
Remarks:
Data of switches, sensors, actuators and so on can be
read through data stream of diagnostic instrument
without removal/installation of any element.
Therefore,
the
reading
of
data
stream
before
troubleshooting is one of the methods for shortening
maintenance time.
Functions of diagnostic instrument shall be determined
based on actual development of customer’s instrument.
Please refer to corresponding instruction manual of
diagnostic instrument for certain vehicle for details.
The diagnostic contents (BOSCH diagnostic instrument)
listed below is only for reference.
(a)
Connect the diagnostic instrument to data link
connector (DLC).
(b) Turn on the ignition switch.
(c)
Read data stream based on display of diagnostic
instrument.
Remarks: Apply the diagnostic instrument to test ABS,
which should be performed in road test. DTC can be
cleared when necessary to ensure normal operation of
ABS and conventional brake system.
Please finish the following procedures before the
replacement of ABS:
1.
Dynamic self-checking: ABS lamp won’t go out
when the ignition switch is turned on again after
some faults (such as wheel speed sensor signal
reliability failure or motor failure) are eliminated
and the lamp shall go out after ABS dynamic
self-checking is qualified with the vehicle speed no
less than 15Km/h.
2.
Cross validation: Install the removed ABS onto a
normal vehicle equipped with the same ABS model,
with ABS harness connectors connected but no oil
pipe in need of connection, and ensure ABS
connectors and wheel speed sensors are firmly and
reliably connected. Start the vehicle to run for a
few circles to enable ABS dynamic self-checking.
�
If the ABS lamp goes out, there is no failure in
ABS.
�
If the lamp keeps on, there is failure in ABS.
The ABS may be replaced.
Item
Display Valve/Range
Normal State
Remarks
Left front wheel speed
1.75Km/h~350Km/h
Actual wheel speed
Right front wheel speed
1.75Km/h~350Km/h
Actual wheel speed
Left rear wheel speed
1.75Km/h~350Km/h
Actual wheel speed
Right rear wheel speed
1.75Km/h~350Km/h
Actual wheel speed
Battery voltage
0~+20.40V
9.3~16.9V
Left front oil inlet valve
ON/OFF
With ignition switch turned on:
Power failure
Other conditions: Based on
control
Relevant to ABS conditions:
Pressure boosting:
Oil inlet valve - power failure
Oil outlet valve - power failure
Pressure maintenance:
Oil inlet valve - continuity
Oil outlet valve - power failure
Pressure reducing:
Oil inlet valve - continuity
Oil outlet valve - continuity
Left front oil outlet valve
ON/OFF
Right front oil inlet valve
ON/OFF
Right front oil outlet valve
ON/OFF
Left rear oil inlet valve
ON/OFF
Left rear oil outlet valve
ON/OFF
Right rear oil inlet valve
ON/OFF
Right rear oil outlet valve
ON/OFF
Brake lamp switch
ON/OFF
ON: With brake pedal
depressed
OFF: With brake pedal released
Reflux pump motor
ON/OFF
Solenoid valve relay
ON/OFF
With ignition switch turned on:
Continuity
Occupied state of hydraulic
governor
Already occupied and normal or
BOSCH supply status
Already occupied and normal
-------------------------------------------------------------------------------------------------------------------------------------------------------------
ABS
ABS
ABS
ABS Anti-lock
Anti-lock
Anti-lock
Anti-lock Brake
Brake
Brake
Brake System
System
System
System
- 82 -
Diagnosis
Diagnosis
Diagnosis
Diagnosis and
and
and
and Testing
Testing
Testing
Testing
Brake
Brake
Brake
Brake bleeding
bleeding
bleeding
bleeding
Note:
Brake bleeding can be performed in the first and second
circuits.
Brake
bleeding
should
be
performed
after
the
replacement of brake system components (such as
change of brake fluid, replacement of brake system
components and hydraulic unit) or when the brake pedal
is soft.
The hydraulic unit for replacement must be wet-type
ABS hydraulic governor with ECU.
During exhaust, please ensure the brake system is of
complete structure and all hydraulic units are properly
connected.
Before brake bleeding, shift to P gear (for AMT) or N
gear (for MT) and apply the parking brake lever.
Brake fluid is toxic, so please clean your skin if any
fluid touches your skin.
1.
Manual brake bleeding procedures
Step
Operation
1
Fill the brake fluid reservoir.
2
Repeat the procedures below for bleeding of
each wheel cylinder in order of left rear, left
front, right front and right rear.
3
Open the bleed screw.
4
Depress and release brake pedal repeatedly.
5
Close the bleed screw.
6
Release the brake pedal.
7
Check the pedal travel.
8
If failed, repeat bleeding.
9
Check if brake fluid level is within upper and
lower limit marks.
Remarks: Brake fluid level in reservoir shall be over the
lower limit mark during the whole bleeding process.
2.
Manual brake bleeding schematic diagram
Manual brake bleeding schematic diagram for 4-channel ABS X type circuit: Left front wheel
Function mode:
The brake fluid flows into wheel cylinder through master cylinder and hydraulic unit. Open the bleed screw on the left
front wheel with the screws on other wheels closed. Depress and release brake pedal until air bubbles and impurities
are fully drained and the brake fluid is pure. Perform the same process on the other three wheels.
-------------------------------------------------------------------------------------------------------------------------------------------------------------
ABS
ABS
ABS
ABS Anti-lock
Anti-lock
Anti-lock
Anti-lock Brake
Brake
Brake
Brake System
System
System
System
- 83 -
Diagnosis
Diagnosis
Diagnosis
Diagnosis and
and
and
and Testing
Testing
Testing
Testing
Component activation test
1.
Component activation test for reflux pump:
(1) Turn off the ignition switch.
(2) Connect the diagnostic instrument to DLC.
(3) Turn on the ignition switch with engine off.
(4) Apply the “Component Test” function of
diagnostic instrument to activate the reflux
pump.
Normal state: Operation sound of reflux pump can
be heard.
2.
Component activation test for solenoid valve:
Remarks:
�
Before testing solenoid valve, please test he
reflux pump to see if it operates normally.
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Two repair men are required to finish this test.
(1)
Turn off the ignition switch.
(2)
Connect the diagnostic instrument to DLC.
(3) One repair man should sit in the vehicle and the
vehicle should be lifted by lifter with wheels
suspended.
(4)
Turn on the ignition switch with engine off.
(5) Apply the “Component Test” function of
diagnostic instrument to activate the solenoid
valve as per prompt of diagnostic instrument.
(6) Firstly, test the oil inlet valve and oil outlet
valve of left front wheel, during which, the
repair man in the vehicle should depress the
brake pedal with force and hold it.
�
Conventional braking phase:
Normal state: The repair man outside
cannot rotate the left front wheel by
hand.
�
Boosting
phase:
Use
diagnostic
instrument
to
access
the
“boosting
phase”.
Normal state: The repair man outside
cannot rotate the left front wheel by
hand.
�
Pressure
maintenance
phase:
Use
diagnostic
instrument
to
access
the
“pressure maintenance phase”.
Normal state: The repair man outside
cannot rotate the left front wheel by
hand.
�
Pressure reducing phase: Use diagnostic
instrument
to
access
the
“pressure
reducing phase”.
Normal state: The repair man outside can
rotate the left front wheel by hand.
(7) Perform testing for right front, left rear and
right rear wheels in sequence. The test results
should be the same as those of left front
wheel.
3.
Component activation test for ABS and EBD
warning lamps
(1) Turn off the ignition switch.
(2) Connect the diagnostic instrument to DLC.
(3) When performing the component activation
test for ABS and EBD warning lamps, they
should lighten or go out corresponding to the
control of diagnostic instrument.
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