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DTC C1011 FL wheel speed sensor signal
DTC C101C FR wheel speed sensor signal
DTC C1027 RL wheel speed sensor signal
DTC C1032 RR wheel speed sensor signal
 
 
caution
  • If there is any problem in the CAN bus lines, an incorrect DTC 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.
 
 
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.
 
 
 
DTC 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 store the relevant DTC.
  • Irregular change in the wheel speed sensor signal
  • Wheel speed sensor signal continuously indicates high value.
 
 
 
TROUBLESHOOTING HINTS
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 magnetization 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
Past trouble
  • When DTC 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 diagnostic procedures, refer to How to treat past trouble (GROUP 00 - How to Use Troubleshooting/How to Treat Past Trouble ).
  • When DTC 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
 
 
 
 
DIAGNOSIS
Required Special Tools:
  • MB991223: Harness Set
  • MB992006: Extra Fine Probe
STEP 1. Scan tool (M.U.T.-IIISE) CAN bus diagnosis.
(1)
cautionTo prevent damage to scan tool (M.U.T.-IIISE), always turn off the power supply mode of the electric motor switch before connecting or disconnecting scan tool (M.U.T.-IIISE).
Connect scan tool (M.U.T.-IIISE). Refer to "How to connect the Scan Tool (M.U.T.-IIISE) ."
(2) Turn on the power supply mode of the electric motor switch.
(3) Diagnose the CAN bus line.
(4) Turn off the power supply mode of the electric motor switch.
Is the check result normal?
Go to Step 3.
Repair the CAN bus lines (Refer to GROUP 54C - CAN Bus Diagnostics Table ). On completion, go to Step 2.
 
STEP 2. DTC recheck after resetting CAN bus lines.
Is DTC No.C1011, C101C, C1027 or C1032 set?
Go to Step 3.
This diagnosis is complete.
 
STEP 3. Check whether the DTC is set again.
Check that DTC No.C100A, C1015, C1020 or C102B is also set.
Is DTC No.C100A, C1015, C1020 or C102B also set?
Perform the diagnosis for DTC No.C100A, C1015, C1020 or C102B (Refer to ).
Go to Step 4.
 
STEP 4. Check the wiring harness between the ASC-ECU connector terminal and the wheel speed sensor connector terminal.
DTC C1011 is set
  • Check of short to power supply, short to ground, and open circuit in FL+, FL- line between ASC-ECU connector and front wheel speed sensor (LH) connector.
DTC C101C is set
  • Check of short to power supply, short to ground, and open circuit in FR+, FR- line between ASC-ECU connector and front wheel speed sensor (RH) connector.
DTC C1027 is set
  • Check of short to power supply, short to ground, and open circuit in RL+, RL- line between ASC-ECU connector and rear wheel speed sensor (LH) connector.
DTC C1032 is set
  • Check of short to power supply, short to ground, and open circuit in RR+, RR- line between ASC-ECU connector and rear wheel speed sensor (RH) connector.
Is the check result normal?
Go to Step 5.
Repair the connector(s) or wiring harness. Then go to Step 11.
 
STEP 5. Check for wheel speed sensor installation.
Check how the wheel speed sensor is installed (Disconnection of wheel speed sensor, loose mounting bolt, etc.).
Is the check result normal?
Go to Step 6.
Reinstall the wheel speed sensor correctly (Refer to <front> or <rear>). Then go to Step 6.
 
STEP 6. Check for wheel speed sensor output current.
Refer to .
Is the check result normal?
Go to Step 7.
Replace the wheel speed sensor (Refer to <front> or <rear>). Then go to Step 10.
 
STEP 7. Check for wheel bearing looseness.
noteLoose 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 End Play Check <front>, GROUP 27 - Wheel Bearing End Play Check <rear>).
Is the check result normal?
Go to Step 8.
Replace the wheel bearing (front) or rear wheel hub assembly (rear) (Refer to GROUP 26 - Front Axle Hub Assembly <front>, GROUP 27 - Rear Axle Hub Assembly <rear>). Then go to Step 11.
 
STEP 8. Check of wheel speed detection encoder.
Check the encoder for adhesion of foreign materials or deformation.
Is the check result normal?
Go to Step 9.
: 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.
: Replace the wheel bearing (front) or rear wheel hub assembly (rear) (Refer to GROUP 26 - Front Axle Hub Assembly <front>, GROUP 27 - Rear Axle Hub Assembly <rear>). Then go to Step 11.
 
STEP 9. Check whether the DTC is set again.
(1) Erase the DTC.
(2) Drive the vehicle at 12 mph (20 km/h) or higher.
noteThe ABS warning light does not turn OFF in some cases unless the vehicle runs at 12 mph (20 km/h) or higher.
Is DTC No.C1011, C101C, C1027 or C1032 set?
Replace the wheel speed sensor (Refer to <front> or <rear>). Then go to Step 10.
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/How to Cope with Intermittent Malfunctions ).
 
STEP 10. Check whether the DTC is set again.
(1) Erase the DTC.
(2) Drive the vehicle at 12 mph (20 km/h) or higher.
noteThe ABS warning light does not turn OFF in some cases unless the vehicle runs at 12 mph (20 km/h) or higher.
Is DTC No.C1011, C101C, C1027 or C1032 set?
Replace the hydraulic unit (integrated with ASC-ECU) (Refer to ). Then go to Step 11.
This diagnosis is complete.
 
STEP 11. Check whether the DTC is set again.
(1) Erase the DTC.
(2) Drive the vehicle at 12 mph (20 km/h) or higher.
noteThe ABS warning light does not turn OFF in some cases unless the vehicle runs at 12 mph (20 km/h) or higher.
Is DTC No.C1011, C101C, C1027 or C1032 set?
Return to Step 1.
This diagnosis is complete.