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