Chery A15 / 480 LHD model. Manual — part 72

Caution: This failure mode is available only when the system can communicate with

the diagnostic instrument (ABS ECU power supply normal) and there is no
DTC.

Check the open circuit of wires between

Yes

ECU and ABS warning lamp controller

Replace harness

No Abnormal

Check the ABS warning lamp controller

Replace

Normal

Replace the ABS ECU

※ABS operation abnormal

Possible Cause

[Description] This problem is related closely to

the driver and road conditions, and
thus it is difficult to diagnose this
failure. However, if there is no DTC
memory, the following checks may be
conducted.

· Improper installation of sensor
· Sensor harness problem
· Sensor damaged
· Gear ring damaged
· Sensor adhered with foreign
material
· Wheel bearing damaged
· ABS HCU (Hydraulic Control
Unit) damaged
· ABS ECU (Electronic Control
Unit) damaged

Normal

Replace the ABS ECU

No

Install it properly

Yes

Abnormal Abnormal

Replace

Normal Normal

Abnormal

Replace

Abnormal Normal

Abnormal

Replace the ABS HCU

Repair or replace

Normal

Replace the connection

Normal

No

Normal

Abnormal

Repair the harness

or connector

正常

更换ABS ECU

Sensor is installed properly or not

Check the sensor output voltage

Use the diagnostic tester to

conduct the HCU diagnosis

Check all sensors

Check all sensor gear rings

Check wheel bearing clearance

Check ABS ECU socket and

intermediate connector

Failure reoccurs or not

Refer to “Repair Details

of Random Failure”

Remove the ABS ECU connector, and check

whether the resistances between the

following terminals of ABS ECU conform to

the standard values?

Standard resistance: 1.0-1.3 kΩ

Measure the resistances, and, at the same

time, swing the sensor harness and connector.

MK20I/E

FL wheel: 1-2 RR wheel: 19-20

RL wheel: 5-6 FR wheel: 22-23

Abnormal

Abnormal

Abnormal

正常

Normal

※Too long brake pedal travel

Possible Cause

[Description] Firstly take the visual inspection to

determine

the

outside

leakage

or

mechanical failure. Use the air bleeding
method to check the air in the system. And
use the diagnostic tester and hydraulic
testing to check the leakage of normally
closed valve (NC valve).

· Brake fluid leakage
· NC valve leakage
· Air kept in the system
· Serious brake disc wear
· Hand brake adjustment
improper

Abnormal

Tighten the pipe joint according to the requirement

Normal

Abnormal

Replace the brake disc

Normal

Abnormal

Replace the hand brake adjusting equipment

Normal

Abnormal

Air bleeding again

Normal

Abnormal

Replace HCU (Hydraulic Control Unit)

※Forcefully step on the brake pedal

Possible Cause

[Description] Use the traditional method to check and control

the booster and brake pedal travel. The failure of NO

(Normally Open) valve can be checked using the

diagnostic tester’s hydraulic control unit function.

· Booster failure
· NO valve failure

Replace HCU (Hydraulic Control Unit)

Visually inspect the leakage of hydraulic

Check the wear condition of brake

Check hand brake adjusting

Air bleeding check

Use the diagnostic tester HCU to

diagnose the sealing of NC valve

Use the diagnostic tester’s HCU to

diagnose and check the NO valve

Use the traditional method available

for ABS vehicle to check the booster

Abnormal

否

Yes

更换

Normal

是

No

Abnormal

导通

No

Replace

Yes

Yes

※Without DTC output (fail to communicate with the diagnostic tester)

Possible Cause

[Description] If it is difficult to communicate with the

diagnostic tester, it is possible that the supply

circuit of ABS ECU or the diagnostic circuit is

open circuit.

· The fuse broken
· The diagnostic circuit broken or

the connection uncoupled
· ABS ECU damaged
· Diagnostic tester failure

No

Repair the diagnostic socket or ABS harness

Replace the ABS ECU

The diagnostic tester communicates with the

MK20 ABS ECU on the other vehicles

Check ABS supply fuse

The diagnostic tester failure, and

conduct the check after repair

Display it on the screen of diagnostic tester or not

Remove ABS ECU’s connections, check the

connection of the ECU related terminals in

ABS harness (terminal 7 for MK20 I/E) with

the diagnostic socket (terminal 7 in the

diagnostic tester)

Check the supply,
earth,

and

diagnostic wires
in the diagnostic
tester socket, and
their connection

Repair the diagnostic

tester socket or harness