Chery B11. Manual — part 100

Eight. C0025 Excessive fluctuation of front left wheel speed

Straddling
wire

Wheel speed sensor

Car body wire harness

Gear
ring

1. Description of circuit
The wheel speed sensor will create an AC
voltage that increases with the increase of
wheel speed. EBCM then calculates the
wheel speed on the basis of the AC signal
frequency. The speed sensor is connected
to the EBCM by a twisted pair which can
reduce the noise vulnerability of
troubleshooting codes.

2. Conditions for setup of
troubleshooting codes
The following conditions will have to be
met for the setup of C0025:
(1) C0032, C0033, C0034 or C0035 is not
current.
(2) ABS does not work.
(3) Braking switch is on.
(4) Front left wheel is accelerating or
decelerating, which exceeds the reasonable
limit.

3. Actions to be taken for setup of
troubleshooting codes
(1) The electromagnetic relay is turned off
and pump motor and solenoid are
disconnected with the power source.
(2) Save DTC C0025.
(3) ABS is disabled and ABS alarm lamp
is on.

4. Conditions for clearing
troubleshooting codes

(1) If the conditions for setting up
troubleshooting code C0025 are gone,
corresponding scanning tools can be used
to clear the troubleshooting code.
(2) If the troubleshooting code does not
appear for 100 driving cycles running, it
can be eliminated from the database.

5. Assistance to troubleshooting
In the case of any interrupted
troubleshooting code, please thoroughly
check the wiring and connectors, which
shall include:
(1) Unfix guard pipes and check if the
wiring is damaged, short circuited and
polluted.
(2) Check if the terminals are deformed
and/or damaged.
(3) Check the contact (fastness) of
terminals by the spare male/female
terminals.
(4) Check if the wire terminals are correct
by unfixing terminals from the connector.
If the driver complains that the ABS alarm
lamp only illuminates when there is a
change in environment moisture (rain,
snow and car washing), please thoroughly
check if any wheel speed sensor is soaked.
If the troubleshooting code is not current,
then simulate the impact of water soaking.
Follow the following steps: spray 5%
brine on suspected area. Then trial run the
car at a speed of over 24km/h (15m/h) on
various road surfaces (e.g. bumpy or

curved road, etc). If any troubleshooting
code appears, then replace the suspected
wire harness and/or sensor.
Check any gear ring carefully to find if
there is any crack or tooth damage. If the
troubleshooting code is set up at the same
speed of each driving cycle, then the gear

ring is highly possible to have been
damaged.
Any failure in carefully and thoroughly
following the above steps will possibly
result in wrong diagnosis, unnecessary
component replacement and reoccurrence
of DTC C0025.

6. Diagnostic steps

Step Diagnostic

action

Expected
value

Yes No

1

If the checking of diagnostic circuit has been
finished

To

Step 2

To Step 12

2

Is DTC C0032 set to be a current and historic
troubleshooting code?

To

Step
13

To Step 3

3

1. Shut off engine
2. Check if the front left wheel speed sensor and
straddling wire harness are damaged?
3. Thoroughly check the front left gear to know
if there is any damage (crack, missing tooth and
loosening)
Is there any physical damage?

To

Step
14

To Step 4

4

1. Park the car
2. Connect the scanning device and select the
data list.
3. Monitor wheel speed sensor
4. Start the car and monitor the wheel speed
sensor when the engine has started running but
the car remains still.
5. Gently step down the accelerator pedal to
increase the engine idle speed.
Is C0025 reset or if the front left wheel speed
exceeds 0 mile/h when the engine is running but
the car remains still?

To

Step
15

To Step 5

5

1. Connect the scanning device.
2. Monitor wheel speed sensor
3. Trial run the car until the setup speed upper
limit is reached; then gradually slow down the
car to zero speed. Repeat the steps several times.
Is C0025 reset or does the front left wheel speed
variation exceed 5km/h (3 mile/h) during driving
if compared with the speed of any other wheel?

To

Step 6

To Step 16

6

1. Park the car
2. Lift and properly support the car.
3. Detach the front left straddling wire harness
from the front left wheel speed sensor.

800-
1,600ohm
(resistance
will

To
Step 7

To Step 17

4. Connect the ohmmeter to the front left wheel
speed sensor terminals A and B.
Is the resistance within the range required?

increase
with
temperature
rise

7

1. The car speed sensor is still detached from the
straddling wire harness.
2. Connect the ohmmeter to the front left wheel
speed sensor terminals A and B.
3. Select AC mV scale.
4. Rotate the front left wheel while observing the
voltmeter.
Is the AC voltage within the range required?

At least
100mV

To
Step 8

To Step 17

8

1. Detach the EBCM wire harness from the
EBCM.
2. Detach the front left straddling wire harness
from the ABS car body wire harness.
3. Connect an ohmmeter to the EBCM terminal
A09 and then to the ABS car body wire harness
terminal A.
Is the resistance within the range required?

Less than
2ohm

To
Step 9

To Step 18

9

1. EBCM wire harness remains detached from
the EBCM.
2. Straddling wire harness still remains detached
from the car body wire harness.
3. Connect an ohmmeter to the EBCM terminal
A10 and then to the ABS car body wire harness
terminal B.
Is the resistance within the range required?

10

1. EBCM wire harness remains detached from
the EBCM.
2. Straddling wire harness still remains detached
from the car body wire harness.
3. Connect an ohmmeter to the EBCM terminals
A09 and A10.
Is the resistance within the range required?

OL open
circuit

To
Step
11

To Step 20

11

1. Replace front left straddling wire harness.
2. Trial run the car at various speeds on various
road surfaces.

To

Step
21

Car
maintenance

12

Check the diagnostic circuit before making the
DTC0025 fault table.

13

Prepare C0032 diagnostic chart before making
the DT0025 fault table.

14

Repair damage to the front left wheel speed
sensor, straddling wire harness and/or gear ring.

15

The cause of C0025 is the noise of ignition
switch coupled to the front left wheel speed

sensor.
Check if there is any potential source of ignition
noise for front left ABS car body wire harness
and/or straddling wire harness, like spark plug
wire, etc. Rearrange the wire as the case may
require.

16

DTC C0025 is intermittent. Refer to “Assistance
to troubleshooting”.

17

Replace the front left wheel speed sensor.

18

Repair the open circuit or high resistance
between terminals A09 and A.

19

Repair the open circuit or high resistance
between terminals A10 and B.

20

Repair the short circuit between two wires.

21

Replace the EBCM.

Nine C0026 Excessive fluctuation of front right wheel speed

Straddling
wire

Wheel speed sensor

Car body wire harness

Gear
ring

1. Description of circuit
The wheel speed sensor will create an AC
voltage that increases with the increase of
wheel speed. EBCM then calculates the
wheel speed on the basis of the AC signal
frequency. The speed sensor is connected
to the EBCM by a twisted pair which can
reduce the noise vulnerability of
troubleshooting codes.

2. Conditions for setup of
troubleshooting codes
The following conditions will have to be
met for the setup of C0026:
(1) C0032, C0033, C0034 or C0035 is not
current.
(2) ABS does not work.

(3) Braking switch is on.
(4) Front right wheel is accelerating or
decelerating, which exceeds the reasonable
limit.

3. Actions to be taken for setup of
troubleshooting codes
(1) The electromagnetic relay is turned off
and pump motor and solenoid are
disconnected with the power source.
(2) Save DTC C0026.
(3) ABS is disabled and ABS alarm lamp
is on.

4. Conditions for clearing
troubleshooting codes