Code No. C1041 FL wheel speed tone performance
Code No. C1042 FR wheel speed tone performance
Code No. C1043 RL wheel speed tone performance
Code No. C1044 RR wheel speed tone performance


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.

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 periodical drop is found in these sensor signals, ASC-ECU will set the relevant diagnosis code.

PROBABLE CAUSES

  • Wheel bearing malfunction
  • Deformation of the wheel speed detection encoder
  • Adhesion of foreign materials on the wheel speed detection encoder
  • ASC-ECU malfunction
  • The number of poles on the Magnetic encoder for wheel speed detection (N-pole and S-pole) is changed

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 Diagnostics Table ). On completion, go to Step 2.

STEP 2. Diagnosis code recheck after resetting CAN bus lines

Q. Is the diagnosis code No.C1041, 1042, 1043 or 1044 set?
Go to Step 3
This diagnosis is complete.

STEP 3. 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 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)>

Q. Is the check result normal?
Go to Step 4
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 6.

STEP 4. 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 5

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. Then go to Step 6.

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 6.

STEP 5. Check whether the diagnosis code is reset.
(1)Erase the diagnosis code.
(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.

Q. Is diagnosis code No. C1041, 1042, 1043 or 1044 set?
Replace the hydraulic unit (integrated with ASC-ECU) (Refer to ). Then go to Step 6.
This diagnosis is complete.

STEP 6. Check whether the diagnosis code is reset.
(1)Erase the diagnosis code.
(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.

Q. Is diagnosis code No. C1041, 1042, 1043 or 1044 set?
Return to Step 1.
This diagnosis is complete.