Engine JAC HFC4DA1-2C. Service manual — part 141
ABS
ABS
ABS
ABS Anti-lock
Anti-lock
Anti-lock
Anti-lock Brake
Brake
Brake
Brake System
System
System
System
85
Diagnosis
Diagnosis
Diagnosis
Diagnosis and
and
and
and Testing
Testing
Testing
Testing
Fault symptom table
If fault occurs without fault memory during DTC reading, please check relevant circuits of each fault symptom in
order listed below and by referring to relevant fault diagnosis content.
Attention:
Attention:
Attention:
Attention:
Before maintenance of ABS, please ensure the conventional brake system operates normally.
When the replacement of ABS hydraulic governor with ECU, sensors or other components is necessary, please turn
off the ignition switch firstly.
Fault Symptom
Check Areas
ABS failed to operate
1. Check if ABS and EBD warning lamps are lit;
2. Read DTC and check for any fault;
3. Check power UZ circuit of ignition switch;
4. Check brake line for any leak.
ABS poor effect
1. Read DTC and check for any fault;
2. Check brake line for any leak;
3. Apply diagnostic instrument to read “occupied state of hydraulic governor”;
4. Check the power supply state of battery;
5. Ensure the mounting bracket is fixed at normal state (at this time the driving comfort
may decrease).
Abnormal ABS and EBD
warning lamps
1. Read DTC and check for any fault;
2. Check the circuits of ABS and EBD warning lamps;
3. Check power UZ circuit of ignition switch;
4. Check the power supply state of battery;
Diagnostic
instrument
failed to read DTC
1. Check if ABS and EBD warning lamps are lit;
2. Check the power line and ground cable of ABS hydraulic governor with ECU;
3. Check power UZ circuit of ignition switch;
4. Check the power supply state of battery;
5. Check the DIAGK cable of ABS hydraulic governor with ECU;
6. Check the diagnostic instrument for reliable connection.
ABS
ABS
ABS
ABS Anti-lock
Anti-lock
Anti-lock
Anti-lock Brake
Brake
Brake
Brake System
System
System
System
86
Diagnosis
Diagnosis
Diagnosis
Diagnosis and
and
and
and Testing
Testing
Testing
Testing
Intermittent fault diagnosis table
Note: In case one of the following conditions occurs, there is intermittent fault.
Fault does not always occur;
It may probably occur again;
There is history DTC but no current DTC.
Inspection
Operation
Preliminary inspection
1. Perform “preliminary inspection” at first;
2. Collect information relevant to the arising of intermittent fault from the customer, such
as:
1) Driving conditions (vehicle speed, brake, warning lamps and road condition) when the
fault occurs.
2) Does the fault occur during the application of electrical equipments added by service
shop?
3) Has the battery status been checked?
4) Have the wheel speed sensor harnesses and gear rings been checked?
Detection by diagnostic
instrument
Detection procedures:
1. Operate the suspicious ABS component harnesses and connectors and observe the data
stream of measured circuit on the diagnostic instrument. If the reading of diagnostic
instrument fluctuates during this operation, please check circuits for loose connection.
2. Perform vehicle road test under occurrence of intermittent fault and ask an assistant to
observe the suspicious operating parameters on the diagnostic instrument.
3. Capture and store data by snapshot once fault occurs. The stored data can be displayed
at lower speed to facilitate diagnosis. Oscilloscope can also be applied for signal
detection.
4. Apply the “Component Test” function of diagnostic instrument to control the
suspicious ABS components to test their operation.
Warning lamps
The following conditions may lead to intermittent illumination of warning lamps without
DTC set.
1. Warning indicator circuit is shorted to ground intermittently.
2. Ground points of ABS hydraulic governor with ECU or instruments become loose.
3. Battery voltage is a little lower or unstable under stationary state of vehicle.
Wheel speed sensor
1. Visually inspect wheel speed sensors and gear rings for looseness, damage, foreign
matters or improper installation. Please replace any damaged component, remove any
foreign matter or fix any loosened component accordingly.
2. Check the wheel speed sensor for proper wiring and ensure the harnesses of wheel
speed sensor are not interfered by mechanical components.
3. Monitor the data display of wheel speed sensor on diagnostic instrument with
assistance and at the same time perform road test to check if any wheel speed sensor in
abnormal speed range is displayed.
Additional testing
1. Check electrical equipments added by service shop such as mobile phones, anti-theft
warning devices, lamps, radio equipments, stereo amplifiers and so on for correct
installation.
2. Check if any electromagnetic interference (EMI) is caused by failed components (such
as relays or solenoid valves) with power on.
3. Power-on test for motors and solenoid valves.
ABS
ABS
ABS
ABS Anti-lock
Anti-lock
Anti-lock
Anti-lock Brake
Brake
Brake
Brake System
System
System
System
87
Diagnosis
Diagnosis
Diagnosis
Diagnosis and
and
and
and Testing
Testing
Testing
Testing
1.
Wheel speed sensor fault (C0035, C0040, C0045, C0050, and C0245): Wheel speed sensors are applied to detect
the wheel speed and transmit relevant signals to ABS ECU. These signals are used for controlling ABS operation.
Each wheel is equipped with a sensor and with a 48-tooth gear ring mounted on its axle shaft. This vehicle model
mainly adopts the active wheel speed sensors that are activated by 12V DC power voltage supplied by ABS ECU.
Wheel speed sensor adopts Hall Effect with nearly constant output amplitude and square wave of 50% duty cycle,
with low voltage of 0.5V and high voltage of 1V; its frequency increases with the increase of vehicle speed. ABS
ECU shall calculate the wheel speed based on this frequency.
Output signals:
Output signals:
Output signals: 0.44~0.63 (low voltage), 0.89~1.26 (high voltage)
Output signals: 0.44~0.63 (low voltage), 0.89~1.26 (high voltage)
U
n
d
er
st
at
io
n
ary
or
Low speed
High speed
U
n
d
er
ru
n
n
in
g
st
at
e
ABS
ABS
ABS
ABS Anti-lock
Anti-lock
Anti-lock
Anti-lock Brake
Brake
Brake
Brake System
System
System
System
88
DTC
Detection Condition
Set Condition
Possible Faulty Areas
C0035
C0040
C0045
C0050
With
the
ignition
switch turned on
All conditions
1) Monitor if the power voltage of sensor is too low;
2) Monitor if the power wire and signal wire of sensor is
normal.
1. Wheel speed sensor bodies
2. Wrong connection of wheel
speed sensors
3. Wheel speed sensor signals
being interfered
4. Too large clearance between
wheel speed sensor and gear
ring (displacement caused by
vibration)
5. Corrosion
of
wheel
speed
sensors and supports
6. Gear ring fault (dirty, tooth
damage)
7. Tires: size, pressure, pattern
and tread depth
8. Connectors
flawed,
contaminated or affected with
damp
9. Loosened or fractured wheel
speed
sensors/connecting
wires/connectors
10. Sensor
circuit
shorted
to
ground
11.Damaged insulation of sensor
cables
Wheel
speed
monitoring
a.Reference vehicle
speed within 0 ~
100Km/h
1) At least one wheel speed above the reference vehicle
speed of 12km/h over 8s (72s is required in case of
wheel skidding;
2) Speed difference between wheels on the same side
(such as left front and left rear wheels) over 6Km/h,
or speed difference between wheels on the same axle
(such as left front and right front wheels) when
turning over 10Km/h, or speed difference between
diagonal wheels (such as left front and right rear
wheels) when turning over 14Km/h.
Wheel speed
monitoring
b. Reference vehicle
speed >100Km/h
Speed difference between wheels on the same side over
6% of the reference speed, or speed difference between
wheels on the same axle when turning over 6%+4Km/h of
the reference speed, or speed difference between diagonal
wheels when turning over 6%+8Km/h of the reference
speed.
Long time monitoring
of signal interference
1) In case signals of one or two wheel speed sensors fail,
fault shall be detected in 20s (with brake pedal
depressed) or 5s (without brake pedal depressed).
2) In case signals of three or four wheel speed sensors
fail, fault shall be detected in 1s.
Monitoring of wheel
speed difference
Perform monitoring when vehicle speed over 20Km/h
and 20s (or 80s in case of wheel skidding) is needed
for fault confirmation:
1) If the vehicle speed is within 20Km/h~100Km/h, the
speed difference between the fastest and slowest
wheels shall exceed 6%;
2) If the vehicle speed is over 100Km/h, the speed
difference between the fastest and slowest wheels
shall exceed 6Km/h;
3) During vehicle turning, vehicle speed difference
range shall increase by 4Km/h.
Gear ring monitoring
For example: Missing
teeth
With vehicle speed of 10~ 60Km/h and no operation of
ABS, missing pulse number per rotation of wheel is
displayed for over 10 times.
Dynamic monitoring
If the vehicle speed is over 43Km/h, no wheel speed
signal is received within 10~20ms in interval of 60ms.
Monitoring
of
fast
starting speed
(only for wheel speed
sensors
of
driving
wheels)
1) With vehicle speed over 12Km/h, the speed of one or
two wheels is below 2.75Km/h;
2) If the speed of one wheel decreases below 2.75Km/h
with running speed of v1 (over 12Km/h), the fault can
be detected when the vehicle speed increases by
18Km/h, viz. speed increase up to v1+18.
Monitoring
of
slow
starting speed
If the speed of two wheels is over 12Km/h and the speed
of the other one or two wheels is below 5Km/h, 20s is
needed for fault confirmation.
With
the
ignition
switch turned on
All conditions
If one of the following faults appears for over 200ms:
1. Sensor wiring circuit open, open to ground or power
supply
2. Loosened sensor connectors
The current of wheel speed sensor is out of range:
Current <1.1mA or >39mA
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