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
| 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 - Troubleshooting
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- Whenever ECU is replaced, ensure that the CAN bus lines are normal.
- When the hydraulic unit assembly (integrated with ASC-ECU) is replaced, always carry
out the calibration of the steering wheel sensor and the G and yaw rate sensor (Refer to and ).
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OPERATION
- 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.
DIAGNOSIS CODE SET CONDITIONS
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.
- Irregular change in the wheel speed sensor signal
PROBABLE CAUSES
Current trouble
- External noise interference
- Damaged wiring harness and connectors
- Malfunction of wheel speed sensor
- Adhesion of foreign materials on the wheel speed sensor
- Adhesion of foreign materials on the rotor (for wheel speed detection)
- Improper installation of the wheel speed sensor
- Malfunction of the hydraulic unit assembly (integrated with ASC-ECU)
- Deformation of the wheel speed detection magnetic encoder
- The number of poles on the wheel speed detection magnetic encoder is changed
- Disturbance of magnetisation pattern for wheel speed detection encoder
Past trouble
- 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 Cope with Intermittent Malfunctions ).
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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 line (Refer to GROUP 54C - Troubleshooting ).
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 diagnosis code No. C1011, C101C, C1027 or C1032 set?
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Go to Step 3.
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The procedure is complete.
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STEP 3. M.U.T.-III data list
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Check the following data list (Refer to ).
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- (When code No. C1011 is set) Item No.01: FL wheel speed sensor
- (When code No. C101C is set) Item No.02: FR wheel speed sensor
- (When code No. C1027 is set) Item No.03: RL wheel speed sensor
- (When code No. C1032 is set) Item No.04: RR wheel speed sensor
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Q.
Is the check result normal?
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Go to Step 7.
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Go to Step 4.
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STEP 4. Harness and connector check
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(1)Check the wheel speed sensor (FL, FR, RL or RR).
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(2)Check the ASC-ECU connector.
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(3)Check the wiring harness and connector between the ASC-ECU connector and the wheel
speed sensor (FL, FR, RL or RR).
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Q.
Is the check result normal?
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Go to Step 5.
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Repair the defective connector or the wiring harness. Then go to Step 8.
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STEP 5. Check of wheel speed detection magnetic encoder are installed
properly
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Check whether the wheel speed detection magnetic encoder relevant to code No. is installed
correctly (adhesion of foreign materials, deformation, etc.).
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Diagnosis code No.
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Relevant sensor
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C1011
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Front left
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C101C
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Front right
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C1027
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Rear left
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C1032
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Rear right
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Q.
Is the check result normal?
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Go to Step 6.
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NO <when the relevant wheel is front> : Remove the foreign materials and clean the encoder so as not to disturb the magnetisation
pattern on it while taking care of the magnet, magnetic substance, and magnetic attraction.
If deformation is found, replace the wheel bearing (Refer to GROUP 26 - Front Axle Hub
Assembly ). Then go to Step 8.
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NO <when the relevant wheel is rear> : Remove the foreign materials and clean the encoder so as not to disturb the magnetisation
pattern on it while taking care of the magnet, magnetic substance, and magnetic attraction.
If deformation is found, replace the pulse rotor (Refer to GROUP 27 - Rear Axle Hub Assembly ).
Then go to Step 8.
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STEP 6. Check for wheel speed sensor as a single unit
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Check the wheel speed sensor (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 ).
Then go to Step 8.
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STEP 7. Check whether the diagnosis code is set again.
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Check again if the diagnosis code is set.
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(1)Erase the diagnosis code.
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(2)Ignition switch: "LOCK" (OFF) position to "ON"
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(3)Drive the vehicle at 60 km/h or more.
| note |
The ABS warning lamp does not turn OFF in some cases unless the vehicle runs at 60 km/h
or higher.
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Q.
Is diagnosis code No. C1011, C101C, C1027 or C1032 set?
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Replace the hydraulic unit assembly (integrated with ASC-ECU) (Refer to ). Then
go to Step 8.
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The trouble can be an intermittent malfunction (Refer to GROUP 00 - How
to Cope with Intermittent Malfunction ).
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STEP 8. Check whether the diagnosis code is set again.
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Check again if the diagnosis code is set.
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(1)Erase the diagnosis code.
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(2)Ignition switch: "LOCK" (OFF) position to "ON"
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(3)Drive the vehicle at 60 km/h or more.
| note |
The ABS warning lamp does not turn OFF in some cases unless the vehicle runs at 60 km/h
or higher.
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Q.
Is diagnosis code No. C1011, C101C, C1027 or C1032 set?
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Return to Step 3.
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This diagnosis is complete.
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