Code No. C1011
FL wheel speed sensor signal
Code No. C101C FR wheel speed sensor
signal
Code
No. C1027 RL wheel speed sensor signal
Code No. C1032 RR wheel speed
sensor signal
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caution |
- If there is
any problem in the CAN bus lines, an incorrect diagnosis code may be
set. Prior to this diagnosis,
diagnose the CAN bus lines (Refer to GROUP 54C - CAN Bus
Diagnostics Table ).
- Whenever ECU is replaced, ensure that the CAN bus lines are
normal.
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- The wheel speed sensor is a kind of a pulse generator. It consists of
encoders
(a plate on which north and south pole sides of the magnets are arranged
alternately) for detecting the
wheel speed which rotates at the same speed of the wheels and wheel speed
sensors. This sensor
outputs frequency pulse signals in proportion to the wheel
speed.
- The pulse signals, which the wheel speed sensor creates, are sent to
ASC-ECU. ASC-ECU
uses the frequency of the pulse signals to determine the wheel
speed.
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DIAGNOSIS CODE SET CONDITIONS
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ASC-ECU monitors the signals from each wheel
speed sensor while the vehicle is being driven.
If any fault below is found in these sensor signals, ASC-ECU will set the
relevant diagnosis code.
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- Irregular change in the wheel speed sensor signal
- Wheel speed sensor signal continuously indicates high value.
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Current trouble
- Excessive gap between the wheel speed sensor and the wheel speed
detection encoder
- Adhesion of foreign materials on the wheel speed sensor
- Adhesion of foreign materials on the wheel speed detection
encoder
- Wheel bearing malfunction
- Malfunction of wheel speed sensor
- Damaged wiring harness and connectors
- External noise interference
- Improper installation of the wheel speed sensor
- Deformation of the wheel speed detection encoder
- ASC-ECU malfunction
- Disturbance of magnetisation pattern for wheel speed detection
encoder
- The number of poles on the Magnetic encoder for wheel speed detection
(N-pole and
S-pole) is changed
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Past trouble
- When diagnosis code No.C100A, C1015, C1020 or C102B is also set,
carry out diagnosis with particular emphasis on wiring harness and
connector failures between
ASC-ECU and the wheel speed sensor. For diagnosis procedures, refer to
How to treat past trouble
(GROUP 00 - How to Use Troubleshooting/How to Treat Past
Trouble ).
- When diagnosis code No.C100A, C1015, C1020 or C102B is not set,
the following conditions may be present:
- Some wheels slip
- Unstable vehicle attitude
- External noise interference
- Vehicle ran with the parking brake applied
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STEP 1. M.U.T.-III CAN bus diagnosis
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Use M.U.T.-III to diagnose the CAN bus
lines.
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Q.
Is the check result normal?
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Go to Step 3.
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Repair the CAN bus lines (Refer
to GROUP 54C - CAN Bus Diagnostics Table ).
On completion, go to Step 2.
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STEP 2. Diagnosis code recheck after resetting CAN bus
lines
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Q.
Is the diagnosis code No.C1011, C101C, C1027 or C1032 set?
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Go to Step 3.
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This
diagnosis is complete.
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STEP 3. M.U.T.-III diagnosis code
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Check that diagnosis code No.C100A, C1015,
C1020 or C102B is also set.
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Q.
Is diagnosis code No.C100A, C1015, C1020 or C102B also set?
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Perform the diagnosis for diagnosis
code No.C100A, C1015, C1020 or C102B (Refer
to ).
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Go to Step 4.
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STEP 4. Check the wiring harness between the ASC-ECU connector terminal
and the wheel speed sensor connector terminal
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Code No.C1011 is set
- Check of short to power supply, short to earth, and open circuit in
FL+,
FL- line between ASC-ECU connector and front wheel speed sensor
(LH) connector.
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Code No.C101C is set
- Check of short to power supply, short to earth, and open circuit in
FR+,
FR- line between ASC-ECU connector and front wheel speed sensor
(RH) connector.
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Code No.C1027 is set
- Check of short to power supply, short to earth, and open circuit in
RL+,
RL- line between ASC-ECU connector and rear wheel speed sensor (LH)
connector.
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Code No.C1032 is set
- Check of short to power supply, short to earth, and open circuit in
RR+,
RR- line between ASC-ECU connector and rear wheel speed sensor (RH)
connector.
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Q.
Is the check result normal?
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Go to Step 5.
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Repair the connector(s) or wiring
harness. Then go to Step 11.
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STEP 5. Check for wheel speed sensor installation
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Check how the wheel speed sensor is installed
(Disconnection of wheel speed sensor, loose
mounting bolt, etc.).
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Q.
Is the check result normal?
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Go to Step 6.
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Reinstall the wheel speed sensor
correctly (Refer to <front> or <rear>).
Then go to Step 6.
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STEP 6. Check for wheel speed sensor output current
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Refer to .
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Q.
Is the check result normal?
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Go to Step 7.
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Replace the wheel speed sensor
(Refer to <front> or <rear>).
Then go to Step 10.
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STEP 7. Check for wheel bearing looseness
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note |
Loose wheel bearing may increase the gap between
the wheel speed sensor and the wheel
speed detection magnet encoder. Check the wheel bearing for looseness.
<Refer to GROUP
26 - Wheel Bearing Axial Play Check . (front),
GROUP 27A - Wheel Bearing Axial Play Check (rear-2WD)
or GROUP 27B - Wheel Bearing Axial Play Check (rear-4WD)>
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Q.
Is the check result normal?
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Go to Step 8.
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Replace the wheel bearing
<front> or rear wheel hub assembly <rear>.
<Refer
to GROUP 26 - Front Axle Hub Assembly (front),
GROUP 27A - Rear Axle Hub Assembly (rear-2WD)
or GROUP 27B - Rear Axle Hub Assembly (rear-4WD)> Then
go to Step 11.
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STEP 8. Check of wheel speed detection encoder
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Check the encoder for adhesion of foreign
materials or deformation.
Q.
Is the check result normal?
Go to Step 9.
NO (Adhesion
of foreign materials) : Remove the foreign materials
and clean the encoder so as not to disturb the magnetization
pattern on it while taking care of the magnet, magnetic substance, and
magnetic attraction.
Then go to Step 11.
NO (Deformation) : Replace the wheel bearing
<front> or rear wheel hub assembly <rear>.
<Refer
to GROUP 26 - Front Axle Hub Assembly (front), GROUP
27A - Rear Axle Hub Assembly (rear-2WD) or GROUP
27B - Rear Axle Hub Assembly (rear-4WD)> Then
go to Step 11.
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STEP 9. Check whether the diagnosis code is reset.
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(1)Erase the diagnosis code.
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(2)Drive the vehicle at 20 km/h or higher.
note |
The ABS warning lamp does not turn OFF in some cases
unless the vehicle runs at 20 km/h
or higher.
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Q.
Is the diagnosis code No.C1011, C101C, C1027 or C1032 set?
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Replace the wheel speed sensor
(Refer to <front> or <rear>).
Then go to Step 10.
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Intermittent malfunction (Refer to
GROUP 00 - How to Use Troubleshooting/How
to Cope with Intermittent Malfunctions ).
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STEP 10. Check whether the diagnosis code is reset.
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(1)Erase the diagnosis code.
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(2)Drive the vehicle at 20 km/h or higher.
note |
The ABS warning lamp does not turn OFF in some cases
unless the vehicle runs at 20 km/h
or higher.
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Q.
Is the diagnosis code No.C1011, C101C, C1027 or C1032 set?
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Replace the hydraulic unit
(integrated with ASC-ECU) (Refer to ). Then
go to Step 11.
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This
diagnosis is complete.
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STEP 11. Check whether the diagnosis code is reset.
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(1)Erase the diagnosis code.
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(2)Drive the vehicle at 20 km/h or higher.
note |
The ABS warning lamp does not turn OFF in some cases
unless the vehicle runs at 20 km/h
or higher.
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Q.
Is the diagnosis code No.C1011, C101C, C1027 or C1032 set?
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Return to Step 1.
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This
diagnosis is complete.
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