289

III. ABS System Check

Item

Ignition

Switch Shift

Terminal Pole

Standard

Unit

Battery Voltage

OFF

25-8

10.1～14.5

V

Battery Voltage

（

solenoid valve）

OFF

9-24

10.1～14.5

V

Power supply

insulation

OFF

8-4

0.00～0.5

V

Ground insulation

OFF

8-24

0.00～0.5

V

Power supply

voltage

ON

8-4

10.1～14.5

V

OFF

Warning light goes off Visual inspection

ON

Warning light goes on Visual inspection

OFF

Warning light goes off Visual inspection

ON

Warning light goes on

for about 1.7 seconds

then goes off

Visual inspection

Brake light switch
pedal not depressed

ON

8-18

0.0～0.5

V

Brake light switch
pedal depressed

ON

8-18

10.0～14.5

V

Diagnostic interface

OFF

Diagnostic interface

K & 7

0.0～0.5

Ω

LF

Wheel Speed

Sensor Resistance

OFF

1-20

1.2～1.3

KΩ

RF

Wheel Speed

Sensor Resistance

OFF

19-20

1.2～1.3

KΩ

LR Wheel Speed
Sensor Resistance

OFF

5-6

1.0～1.3

KΩ

RR Wheel Speed
Sensor Resistance

OFF

22-23

1.0～1.3

KΩ

LF Wheel Sensor
Output Voltage

OFF

1-2

3.4～14.8

MV/Hz

RF Wheel Sensor
Output Voltage

OFF

19-20

3.4～14.8

MV/Hz

LR Wheel Sensor
Output Voltage

OFF

5-6

>12.2

MV/Hz

RR Wheel Sensor
Output Voltage

OFF

22-23

>12.2

MV/Hz

Speed Sensor Output
Voltage Ratio

ABS Warning Light

ECU not connected

Connect ECU

Maximum peak voltage

Minimum peak voltage

≦2

290

Note: This inspection uses the "03  HCU diagnosis" of the Scan Meter.

Item

Key Switch

Action

Standard

Notes

ON

Depress the pedal

When LF wheel can not
rotate, the pedal does
not descend

Normally-closed

valve inspection

ON（two valves

and pumps are

energized

simultaneously）

Depress the pedal

LF wheel can rotate
freely, the pedal does
not descend

Normally-open

valve inspection

ON

Depress the pedal

When RF wheel can not
rotate, the pedal does
not descend

Normally-closed

valve inspection

ON（two valves

and pumps are

energized

simultaneously）

Depress the pedal

RF wheel can rotate
freely, the pedal does
not descend

Normally-open

valve inspection

ON

Depress the pedal

When LR wheel can not
rotate, the pedal does
not descend

Normally-closed

valve inspection

ON（two valves

and pumps are

energized

simultaneously）

Depress the pedal

LR wheel can rotate
freely, the pedal does
not descend

Normally-open

valve inspection

ON

Depress the pedal

When RR wheel can
not rotate, the pedal
does not descend

Normally-closed

valve inspection

ON（two valves

and pumps are

energized

simultaneously）

Depress the pedal

RR wheel can rotate
freely, the pedal does
not descend

Normally-open

valve inspection

RR wheel
normally-open
and closed valves
seal performance

Note: The vacuum booster must have vacuum applied when performing the following
inspection.

LF Wheel
normally-open
and closed valves
seal performance

RF wheel
normally-open
and closed valves
seal performance

LR wheel
normally-open
and closed valves
seal performance

291

IV. ABS Operation Inspection

1. Check the Wheel Speed Sensor Output Voltage

1

Check whether the clearance between the wheel speed sensor and the ring gear is within the specification

For front wheel standard value, refer to "Front Wheel Sensor Installation Drawing"

For rear wheel standard value, refer to "Rear Wheel Sensor Installation Drawing"

3

Jack up the wheel and release the manual brake

2

Remove the ABS wire harness, measure at the wire harness connector

4

Rotate the wheel at the speed of 1/2 turn/second, and use the multimeter or oscilloscope to measure the

output voltage

Terminal 1-2

Terminal 19-20

Terminal 5-6

Terminal 22-23

Output Voltage

When use the multimeter to measure

For front wheel, refer to "Front Wheel Sensor Drawing".

For rear wheel, refer to "Rear Wheel Sensor Drawing".

When use the oscilloscope to measure

For front wheel, refer to the related standard.

For rear wheel, refer to the related standard.

5

The fact that the output voltage is not within the above range may result from the following causes:

Excessive clearance between the sensor and the ring gear.

Sensor fault.

Check the sensor resistance£¨1.0 - 1.3k¦¸£©.

Select the 4 points on the ring gear to check the clearance (ring gear distortion) between the ring

gear and the wheel speed sensor.

2.Check the Hydraulic Control Unit (HCU).

1

Jack up the vehicle, make sure the wheel can rotate freely.

2

Release the manual brake.

3

Turn the ignition switch to ON after connecting the scan meter, do not start the engine this time.

4

Refer to the HCU Diagnosis for inspection.

Note: when connecting or removing the scan meter, the ignition switch must be turned to OFF.

292

Section 3 Removal and Installation

I.Precautions for Removal

1. Use the scan meter to locate the fault causes before proceeding to service.

2. wipe the surface clean with the cleaning agent without mineral oil before service; be careful to keep it

clean during service, only the lint-free cloth can be used to wipe the removed parts.

3. Only the original spare part can be used, and the package of the new spare part shall not be removed until

the installation.

4. Return liquid pump motor and the HCU is a type of integral structure and can not be separated.

5. When the system is opened, do not use compressed air or move the vehicle.

6. Use proper plug to clog each hydraulic outlet as soon as the ABS assembly is removed.

7. Remove other components that may interfere.

8. Please use the DOT 4 brake fluid, do not use the mineral oil.

9. Use the brake fluid to immerse the seal and the O ring, do not use the engine oil or brake grease.

10. After service, check the regular brake system and ABS brake function for normal and reliable operation.

11. Check all hydraulic pipe union for leakage.

II. HECU Removal

1. Turn off the ignition switch and disconnect the battery negative ground cable.

2. Remove the wire connector from the ABS HECU assembly.

3. Depress the brake pedal >60mm and hold it with the pedal retainer to close the master cylinder center

valve so that the brake fluid will not flow out from the outlet when the system is opened.

4. Put a clean cushion under the hydraulic regulator.

5. Remove the brake pipe (A, B) on the HCU connected to the master cylinder and place the mark, then

use a plug to clog the outlet immediately.

6. Remove the brake fluid pipe(1-4) leading to the wheels, then use a plug to clog the outlet immediately.

7. Remove the nut attaching the HECU to the bracket.