Code No. C1014 Mutual monitoring of FL wheel speed sensor


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, Trouble code diagnosis ).

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 ABS-ECU. ABS-ECU uses the frequency of the pulse signals to determine the wheel speed.

DIAGNOSIS CODE SET CONDITIONS
ABS-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, ABS-ECU will set the relevant diagnosis code.

  • Missing wheel speed sensor signal
  • Wheel speed sensor signal continuously indicates low value than the other wheel speed sensor signals.

PROBABLE CAUSES
Current trouble
  • Excessive gap between the wheel speed sensor and the magnetic encoder for wheel speed detection
  • Wheel bearing malfunction
  • Deformation of the magnetic encoder for wheel speed detection
  • Adhesion of foreign materials on the wheel speed sensor
  • Adhesion of foreign materials on the magnetic encoder for wheel speed detection
  • Malfunction of wheel speed sensor
  • Improper installation of the wheel speed sensor
  • ABS-ECU malfunction
  • Disturbance of magnetization pattern for magnetic encoder for wheel speed detection
  • The number of poles on the magnetic encoder for wheel speed detection (the number of N-pole and S-pole) is changed.
Past trouble
  • When the diagnosis code No. C100A is also set, carry out diagnosis with particular emphasis on wiring harness and connector failures between ABS-ECU and the wheel speed sensor. For diagnosis procedures, refer to How to treat past trouble (GROUP 00 - How to Cope with Intermittent Malfunction ).
  • When the diagnosis code No. C100A 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.
    • Only two wheels are rotated on a drum tester.

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III CAN bus diagnosis
Use M.U.T.-III to diagnose the CAN bus lines.

Q. Is the check result normal?
Go to Step 3.
Repair the CAN bus lines (Refer to GROUP 54C - CAN Bus Diagnosis table ). On completion, go to Step 2.

STEP 2. Diagnosis code recheck after resetting CAN bus lines

Q. Is the diagnosis code No. C1014 set?
Go to Step 3.
This diagnosis is complete.

STEP 3. M.U.T.-III diagnosis code
Check that the diagnosis code No. C100A is also set.

Q. Is the diagnosis code No. C100A also set?
Perform the diagnosis for the diagnosis code No. C100A (Refer to ).
Go to Step 4.

STEP 4. Check for wheel speed sensor installation
Check how the wheel speed sensor <FL> is installed (Disconnection of wheel speed sensor, loose mounting bolt, etc.).

Q. Is the check result normal?
Go to Step 5.
Reinstall the wheel speed sensor <FL> correctly (Refer to ).

STEP 5. Check for wheel speed sensor as a single unit
Refer to .

Q. Is the check result normal?
Go to Step 6.
Replace the wheel speed sensor <FL> (Refer to ).

STEP 6. Check for wheel bearing looseness
note Loose wheel bearing may increase the gap between the wheel speed sensor and the wheel speed detection magnet encoder. Check the wheel bearing <FL> for looseness (Refer to GROUP 26 - On-vehicle Service ).

Q. Is the check result normal?
Go to Step 7.
Replace the wheel bearing (Refer to GROUP 26 - Front axle hub assembly ).

STEP 7. Check of wheel speed detection encoder

Check the encoder for adhesion of foreign materials or deformation.

Q. Is the check result normal?

Go to Step 8.

NO (Adhesion of foreign materials) : 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.

NO (Deformation) : Replace the wheel bearing (Refer to GROUP 26 - Front axle hub assembly ).

STEP 8. Check whether the diagnosis code is reset.
(1)Erase the diagnosis code.
(2)Drive the vehicle at 20 km/h or more.
note The ABS warning lamp does not turn OFF in some cases unless the vehicle runs at 20 km/h or higher.

Q. Is the diagnosis code No. C1014 set?
Replace the ABS-ECU (Refer to ).
Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).