Content .. 142 143 144 145 ..

Engine JAC HFC4DA1-2C. Manual - part 144

ABS

ABS Anti-lock

Anti-lock

Anti-lock Brake

Brake

Brake System

System

Diagnosis

Diagnosis and

and

and Testing

Testing

ABS brake lamp switch circuit fault: C0161

Circuit description:

Brake lamp switch is a kind of normally open switch.

This switch shall be on with the brake pedal depressed, providing +12V signal voltage to brake lamp signal circuit
(+BLS).

ABS ECU shall monitor the brake lamp switch signal voltage to facilitate the determination of brake engagement time
and the detection of brake lamp switch circuit.

DTC

Detection Condition

Set Condition

Possible Faulty Areas

C0161

1. With ignition switch turned on

2. Battery voltage＞8V

3. Vehicle speed＞16Km/h

1. The brake pedal is detected to

depressed

under

the

conditions below:

Vehicle speed＞40Km/h

Acceleration＞8Km/h2

2. The brake pedal is detected to

released

under

the

conditions below:

Vehicle speed＞24Km/h

Acceleration＞11.5Km/h2

1. Brake lamp switch

2. Brake

lamp

switch

circuit

3. Brake

lamp

switch

connector

4. ABS ground

5. ABS

hydraulic

governor with ECU

Troubleshooting

Troubleshooting procedures:

procedures:

S/N

Operating Step

Operation

Detection

Result

Next Step

Checking brake lamp switch
block

(a) Depress and release brake pedal to check brake lamp.

With brake pedal depressed: Brake lamp shall be lit.

With brake pedal released: Brake lamp shall go out.

Remarks: Please ensure the brake lamp and its circuit
is normal when using this method to diagnose the
brake lamp switch.

(b) Check brake lamp switch based on data stream of

diagnostic instrument.

With brake pedal depressed: “Engagement” shall be
displayed on diagnostic instrument.

With brake pedal released: “Disengagement” shall be
displayed on diagnostic instrument.

Normal

Go to the next step.

Abnormal

Go to Step 4

Checking pin voltage of
ABS

hydraulic

governor

with ECU (Voltage of Pin
30 corresponding to

38)

(a) Turn off the ignition switch.

(b) Remove connector from ABS hydraulic governor.

(d) Use multimeter to measure the voltage between brake

lamp switch terminal and grounding terminal.

With brake pedal depressed: Voltage＜2V→Brake
lamp shall be lit.

With brake pedal released: Voltage ＞ 4.5V→Brake
lamp shall go out.

Normal

Go to the next step.

Abnormal

Replace ABS with
hydraulic governor.

Checking connecting wire
and

connector

(between

brake lamp switch and ABS
hydraulic

governor

with

ECU)

Checking connecting wire and connector between brake lamp switch and ABS hydraulic
governor for short circuit or open circuit.

Checking connecting wire
and connector (brake lamp
switch circuit)

Check the brake lamp switch circuit for short circuit or open circuit.

Final inspection.

Confirm that the fault shall no longer appear.

ABS

ABS Anti-lock

Anti-lock

Anti-lock Brake

Brake

Brake System

System

Diagnosis

Diagnosis and

and

and Testing

Testing

ABS ECU fault: C0550

Circuit description:

ABS ECU, installed in ABS hydraulic governor with ECU, is the control center of ABS system. Programmable and
calibration data required by ABS operation are stored in ROM of ABS ECU. ABS ECU shall perform self-checking
continuously to monitor any fault in ABS system.

DTC

Detection Condition

Set Condition

Possible Faulty Areas

C0550

With ignition switch turned on

With engine running and under
all conditions

Under all conditions

Fault is detected immediately.

It is detected that wheel speed sensor
power circuit is short to Uz.

1. ABS

hydraulic

governor with ECU.

2. Circuit.

Occurrence of fault shall give rise to the following operation:

Braking Strategy

Failure Protection

Stop operation

�

Brake system shall enter the conventional braking mode.

�

ABS and EBD warning lamps shall be lit.

Troubleshooting

Troubleshooting procedures:

procedures:

S/N

Operating Step

Operation

Detection Result

Next Step

ABS

hydraulic

governor

with

ECU

under stationary state
of vehicle

(a) Turn off the ignition switch;

(b) Turn on the ignition switch without brake pedal

depressed;

necessary use diagnostic instrument to read DTC.

Normal state: ABS/EBD warning lamp shall go out
without current DTC.

Normal

Check

based

other DTC.

Abnormal

Go to the next step.

Detection of system

circuit

(a) Check all ground circuit of ABS hydraulic governor

with ECU for excessive resistance or open circuit.

(b) Check ABS fuse and when necessary replace it.

excessive resistance, open circuit or short to ground.

(d) Check if the wheel speed sensor power line is short to

main power line.

(e) Check for any electromagnetic interference.

Is the fault eliminated?

Yes

Go to Step 4

Go to the next step.

Replacement of ABS
hydraulic

governor

with ECU.

Replace the ABS hydraulic governor with ECU as a whole.

Conduct

final

inspection to confirm
the fault is removed.

(a)

Clear DTC.

(b)

With ignition switch turned on, ABS has no DTC memory.

ABS

ABS Anti-lock

Anti-lock

Anti-lock Brake

Brake

Brake System

System

Diagnosis

Diagnosis and

and

and Testing

Testing

Voltage out of range: C0800

Circuit description:

ABS ECU monitors the battery power supply voltage supplied to ABS ECU through Uz. If the voltage is out of the
specified range, the following faults shall occur:

Too low voltage supplied to ABS ECU may lead to abnormal operation of ABS system.

Too high voltage supplied to ABS ECU may lead to damage of ABS components.

Normal operating voltage of system: 9.3V～16.9V under operation of reflux pump motor

DTC

Detection
Condition

Set Condition

Possible Faulty Areas

C0800

With

ignition

switch

turned

1. If the voltage is below 9.6V with no operation

of ABS, or below 9.3V with operation of ABS,
this DTC shall be recorded and ABS shall be
turned off by software.

2. If voltage below 7.6V or above 16.9V is

continuously monitored, this DTC shall be
recorded and ABS and EBD shall be turned off
by hardware.

1. Overdischarge or damage of

battery.

2. Fault of voltage regulator

(charging system).

3. Fault of fuse or connector,

imperfect body grounding, or
contact resistance.

Occurrence of fault shall give rise to the following operation:

Braking Strategy

Failure Protection

Normal operation of reflux pump motor and solenoid
valve cannot be ensured.

Brake system shall enter the conventional braking
mode.

ABS and EBD warning lamps shall be lit.

If the voltage is far below 9.6V

The system shall be converted to EBD emergency
control mode.

ABS warning lamp shall be lit.

If the voltage is far above 7.6V

Brake system shall enter the conventional braking
mode.

ABS and EBD warning lamps shall be lit.

Voltage Uz is above 9.8V after a period of too low
voltage.

System shall retreat from the EBD emergency
operation mode.

Normal operation of ABS shall recover.

ABS

ABS Anti-lock

Anti-lock

Anti-lock Brake

Brake

Brake System

System

100

Troubleshooting

Troubleshooting procedures

procedures

S/N

Operating Step

Operation

Detection
Result

Next Step

Checking fuse

(a) Check if the 10A, 25A and 40A fuses for power supply

ECU of ABS operate normally.

Normal: Continuity

Yes

Go to the next step.

Check fuse circuit.

Using multimeter to
check battery voltage

(a) Check battery voltage under various conditions.
① Idling: with headlamp turned on, A/C turned to the

coldest mode/blower turned to the maximum speed
mode

② Parking: With all electrical equipments turned off,

rotation speed increased to 3500rpm and hold on for 30s

③ During application of service brake

Normal value: 10～16.9V

Yes

Go to the next step.

Check

charging

system.

Using

diagnostic

instrument

read

battery voltage

(a) Connect the diagnostic instrument to read battery

voltage under various conditions.

① Idling: with headlamp turned on, A/C turned to the

coldest mode/blower turned to the maximum speed
mode

② Parking: With all electrical equipments turned off,

rotation speed increased to 3500rpm and hold on for 30s

③ During application of service brake

Normal value: 10～16.9V

Yes

Intermittent fault, go
to Step 5

Go to the next step.

Checking voltage of
ABS power line and
ground cable

(a) Turn off the ignition switch.

(b) Remove connectors from ABS hydraulic governor with

ECU.

measure if driving voltage of each solenoid valve, motor
or ECU is between 9.3V～16.9V.

Normal

Go to the next step.

Abnormal

Check

and

repair

circuit.

Fault reconfirmation

(a) Simulate fault for reconfirmation.

(b) Read DTC.

Normal state: No DTC memory

Normal

Go to the next step.

Abnormal

Replace

the

ABS

hydraulic

governor

with ECU.

Intermittent fault

(a) If it is intermittent fault, please return the vehicle to customer, for the fault cannot be located at that

moment.

(b) Ask the customer to record relevant data once the same fault occurs:

Vehicle speed

With/without brake pedal depressed

Weather

Road condition and etc.

Conduct

final

inspection to confirm
the fault is removed.

(a) Clear DTC

(b) With ignition switch turned on, ABS has no DTC memory.

Content .. 142 143 144 145 ..