Content .. 140 141 142 143 ..

Engine JAC HFC4DA1-2C. Manual - part 142

ABS

ABS Anti-lock

Anti-lock

Anti-lock Brake

Brake

Brake System

System

Occurrence of fault shall give rise to the following operation:

Braking Strategy

Failure Protection

Relevant wheels cannot be controlled any more because correct
wheel speed sensor signals cannot be obtained. When fault occurs,
ABS shall make the pressure of front wheels increase and that of
rear wheels decrease until the ignition switch is turned off.

�

The system shall be converted to EBD
emergency control mode.

�

ABS warning lamp shall be lit.

If failure of one or two wheel speed sensors is detected in ABS
control process, the system shall be converted to EBD emergency
control mode until this control process is finished.

�

The system shall be converted to EBD
emergency control mode.

If failure of three or four wheel speed sensors is detected,

�

Brake system shall enter the conventional
braking mode.

�

ABS and EBD warning lamps shall be lit.

Remarks: If the ignition switch is turned on after fault removal, the warning lamp shall go out only when the vehicle
speed exceeds 12Km/h.

Troubleshooting

Troubleshooting procedures

procedures

S/N

Operating Step

Operation

Detection
Result

Next Step

Fault confirmation

(a) Connect the diagnostic instrument, read and record

DTC.

(b) Clear of DTC: Apply diagnostic instrument to clear

DTC as per prompt of the instrument.

Remarks: DTC cannot be cleared if the battery is
removed.

Please ensure normal voltage of battery before

removing fault.

Yes

If it is current fault, please go
to Step 3

If it is history fault, please go
to the next step.

Intermittent

fault

diagnosis

(a) Check wiring between ABS hydraulic governor with

ECU and wheel speed sensors and relevant connectors.
Please refer to “04-Inspection before diagnosis” for
inspection methods and procedures.

(b) Check the free travel of hub bearing.

Normal value of free travel of hub bearing: 0mm

Is the problem solved?

Yes

Go to Step 11

Go to Step 4

Appearance
inspection

(a) Check wiring between ABS hydraulic governor with

ECU and wheel speed sensors and relevant connectors.
Please replace it when necessary.

(b) Check tires:

1. Check every tire size and perform replacement when

necessary.

2. Check tires and wheel hubs for any damage; perform

repair or replacement when necessary.

3. Check tire pressure and make adjustment when

necessary.

4. Check tire pattern for any abnormal wear (eccentric

wear, excess wear, uneven wear and depth); perform
replacement or make tire balance, four-wheel alignment
and girder correction when necessary.

Is the problem solved?

Yes

Go to Step 12

Go to the next step.

ABS

ABS Anti-lock

Anti-lock

Anti-lock Brake

Brake

Brake System

System

S/N

Operating Step

Operation

Detection
Result

Next Step

Using

diagnostic

instrument to read
wheel speed data
stream

(a) Connect the diagnostic instrument to read data stream.

(b) One repair main conduct test run uniformly in a straight
line on good road surface and the other one observe the
data stream.

Normal state: The displayed speed of each wheel is
basically the same.

Tip: Allowable error for speedometer is ±10%.

Normal

Go to Step 8

Abnormal

Check wheel speed sensors.

Checking

wheel

speed sensors

(a)

Remove the connector of wheel speed sensor to

measure the internal resistance of wheel speed sensor.

Normal value: 3MΩ～5MΩ

(b) Measure the wheel speed sensor’s resistance to ground.

Normal value: ∞

Normal

Go to the next step.

Abnormal

Replace relevant wheel speed
sensor.

Ensuring

the

wheel

speed

sensor

correctly

connected

Use multimeter to measure the cable resistance.

Normal value: 0Ω

Normal

Go to the next step.

Abnormal

Repair or replace it.

Using oscilloscope
to

check

wheel

speed sensor and
its waveform

(a) Remove the connector from wheel speed sensor.

(b) One terminal of sensor is connected with 12V battery

and the other terminal connected with red pen of
oscilloscope.

Attention: Ground cable of oscilloscope must be connected
with ground cable of battery.

Please drive carefully and ensure connecting wire not
interfered with motion parts of vehicle.

Normal

Repair or replace the ABS
assembly.

Abnormal

Go to the next step.

Checking

wheel

speed

sensor

harness

Wheel speed sensor adopts twisted pair to provide effective
shield so as to protect sensitive electronic elements from
being affected by electrical interference.

To avoid performance degradation due to electrical
interference, the following requirements should be satisfied
during maintaining the twisted pair:

(a) Wind the wire by 9 loops every 310mm along the

length direction of the wire.

(b) The external diameter of twisted pair shall be no more

than 6.0mm.

Normal

Go to the next step.

Abnormal

Repair

Checking

the

installation

wheel

speed

sensor

Normal

Go to the next step.

Abnormal

Repair

Checking

wheel

speed sensor probe

Normal

Go to the next step.

Abnormal

Clean or replace it.

Checking

wheel

speed sensor rotor

Normal

Check or replace the ABS
assembly.

Abnormal

Clean or replace the gear
ring.

Conduct final inspection to confirm the fault is removed. Clear DTC.

ABS

ABS Anti-lock

Anti-lock

Anti-lock Brake

Brake

Brake System

System

Diagnosis

Diagnosis and

and

and Testing

Testing

Hydraulic governor solenoid valve fault: C0060, C0065, C0070, C0075, C0080, C0085, C0090, C0095

Circuit

Circuit description

description

description::::

With the ignition switch turned on and ABS solenoid valve relay powered on, battery voltage can be provided to one
terminal of solenoid valve of hydraulic governor.

With ignition switch turned off or ABS system disabled, the solenoid valve relay should be kept power-on.

Function:

ABS ECU is applied to control the operation of solenoid valves through controlling their grounding so as to regulate
brake pressure of each brake circuit.

Inlet valves: PWM type.

Outlet valves: Switch type.

DTC

Detection Condition

Set Condition

Possible Faulty Areas

C0060

C0065

C0070

C0075

C0080

C0085

C0090

C0095

To be conducted at the
same time of ABS
ECU initialization and
self-checking:

Vehicle

under

stationary

state

speed ≥15Km/h

1. With the ignition switch turned on, ABS ECU

detects relevant solenoid valve circuit short to
power

ground

permanently

intermittently.

2. Activate relevant solenoid valve but without

feedback.

3. Coil or connector fault of solenoid valve is

detected during travelling:

–

Without brake pedal depressed: Vehicle under
stationary state

–

With brake pedal depressed: Vehicle speed
≈15Km/h

4. Under all conditions, fault occurs in oil

circuit of ABS hydraulic governor with ECU.

1. Fault of solenoid valve

inside ABS hydraulic
governor

with

ECU:

brake oil circuit fault,
electrical fault.

2. Hydraulic/mechanical

fault.

Occurrence of fault shall give rise to the following operation:

Braking Strategy

Failure Protection

Solenoid valve failed to operate or operating wrongly

If the solenoid valve failed to operate, relevant wheel
may be locked. If it operates wrongly, no oil pressure
shall be established for relevant wheel.

Brake system shall enter the conventional braking mode.

ABS and EBD warning lamps shall be lit.

ABS

ABS Anti-lock

Anti-lock

Anti-lock Brake

Brake

Brake System

System

Troubleshooting

Troubleshooting procedures

procedures

S/N

Operating Step

Operation

Detection

Result

Next Step

Checking

ABS

hydraulic

governor

with

ECU

under

stationary

state

vehicle

(a) Turn off the ignition switch;
(b) Turn on the ignition switch without brake pedal depressed;
(c) Check if ABS and EBD warning lamps are lit and when

necessary use diagnostic instrument to read DTC. If it is
normal, ABS/EBD warning lamp shall go out without
current DTC.

Normal

Go to the next step.

Abnormal

Go to Step 3

Using

diagnostic

instrument to perform
component testing for
solenoid

valve

ABS

hydraulic

governor with ECU

Remarks:
① Before testing solenoid valve, please test he reflux pump to

see if it operates normally.

② Two repair men are required to finish this test.
(a)

Turn off the ignition switch;

(b)

Connect the diagnostic instrument to DLC;

(c)

One repair man should sit in the vehicle and the vehicle

should be lifted by lifter with wheels suspended;

(d)

Turn on the ignition switch with engine off;

(e)

Apply the “Component Test” function of diagnostic

instrument to activate the solenoid valve as per prompt of
diagnostic instrument;

(f) 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.

① Conventional braking phase

Normal state: The repair man outside cannot rotate the left

front wheel by hand.

② Boosting phase: Use diagnostic instrument to access the

“boosting phase”.

Normal state: The repair man outside cannot rotate the left

front wheel by hand.

③ 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.

④ 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.

(g) 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.

Normal

Go to the next step.

Abnormal

Replace

ABS

control

unit assembly.

Checking pin voltage
of

ABS

hydraulic

governor with ECU

(a) Turn off the ignition switch;
(b) Remove connectors from ABS hydraulic governor with

ECU;

terminal and grounding terminal of solenoid valve.

Remarks:
If no jumper box is applied, the normal detection cannot be
ensured.
Normal value: U = 9.3 ～ 16.9V

Normal

Replace

ABS

control

unit assembly.

Abnormal

Go to the next step.

Checking connecting
wires, connectors and
40A fuse

(a) Check if 25A fuse is normal;
(b) Check the charging system, such as generator/battery and

its connecting wire;

Normal

Go to the next step.

Abnormal

Replace

repair

connecting
wire/connector or fuse.

Final inspection

(a) Clear DTC;
(b) ABS and EBD warning lamps shall go out shortly after the ignition switch is turned on;
(c) With the ignition switch turned on, C0060, C0065, C0070, C0075, C0080, C0085, C0090 or C0095

DTC shall not appear any more after self-checking is finished by system.

Content .. 140 141 142 143 ..