Code No. C1041:
FL wheel speed sensor tone performance
Code No. C1042: FR wheel speed sensor tone performance
Code
No. C1043: RL wheel speed sensor tone performance
Code No. C1044: RR wheel speed sensor
tone performance
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- 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
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- Whenever ECU is replaced, ensure that the CAN bus lines are normal.
- When the hydraulic unit (integrated with ASTC-ECU) is replaced, always carry out
the calibration of the steering wheel sensor and the G and yaw rate sensor (Refer to ).
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OPERATION
- A toothed rotor (for wheel speed detection) generates
a voltage pulse as it moves across the pickup field of each wheel speed sensor.
- The wheel speed sensor transmit the frequency of the pulses to the ASTC-ECU.
- The hydraulic unit assembly (integrated with ASTC-ECU) modulates the amount of braking force
individually applied to each wheel cylinder.
DIAGNOSIS CODE SET CONDITIONS
ASTC-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, ASTC-ECU will set the relevant
diagnosis code.
- External noise interference of the wheel speed sensor
PROBABLE CAUSES
Current trouble
- Malfunction of the wheel speed sensor
- Malfunction of the front hub assembly
- Teeth lack or clogging of the rotor (for wheel speed detection).
- Adhesion of foreign materials on the rotor (for wheel speed detection)
- Damaged wiring harness and connectors
- Malfunction of the hydraulic unit assembly (integrated with ASTC-ECU)
Past trouble
- Carry out diagnosis with particular emphasis on wiring harness and
connector failures between ASTC-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 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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(1)Turn the ignition switch to the "ON" position.
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(2)Turn the ignition switch to the "LOCK" (OFF) position.
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(3)Drive the vehicle at 15 km/h or more.
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The ABS warning lamp does not turn OFF in some cases unless the vehicle runs at 15 km/h
or higher.
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(4)Erase the diagnosis code.
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Q.
Is diagnosis code No. C1041, C1042, C1043 or C1044 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. C1041 is set) Item 12: FL wheel speed sensor
- (When code No. C1042 is set) Item 13: FR wheel speed sensor
- (When code No. C1043 is set) Item 14: RL wheel speed sensor
- (When code No. C1044 is set) Item 15: RR wheel speed sensor
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Q.
Is the check result normal?
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Go to Step 6.
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Go to Step 4.
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STEP 4. Rotor (for wheel speed detection) check
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Check the Rotor (for wheel speed detection) (Refer to GROUP 35B, Wheel Speed Sensor - Inspection ).
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Q.
Is the check result normal?
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Go to Step 5.
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Replace the rotor (for wheel speed detection). Then go to Step 7.
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STEP 5. Check for wheel speed sensor as a single unit
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Check the wheel speed sensor (Refer to GROUP 35B, Wheel Speed Sensor - Inspection ).
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Q.
Is the check result normal?
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Go to Step 6.
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Repair or replace the wheel speed sensor (Refer to ).
Then go to Step 7.
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STEP 6. Check whether the diagnosis code is set again.
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(1)Turn the ignition switch to the "ON" position.
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(2)Turn the ignition switch to the "LOCK" (OFF) position.
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(3)Drive the vehicle at 15 km/h or more.
| note |
The ABS warning lamp does not turn OFF in some cases unless the vehicle runs at 15 km/h
or higher.
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(4)Erase the diagnosis code.
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Q.
Is diagnosis code No. C1041, C1042, C1043 or C1044 set?
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Replace the hydraulic unit assembly (integrated with ASTC-ECU) (Refer to ). Then
go to Step 7.
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Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent
Malfunctions ).
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STEP 7. Check whether the diagnosis code is set again.
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(1)Turn the ignition switch to the "ON" position.
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(2)Turn the ignition switch to the "LOCK" (OFF) position.
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(3)Drive the vehicle at 15 km/h or more.
| note |
The ABS warning lamp does not turn OFF in some cases unless the vehicle runs at 15 km/h
or higher.
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(4)Erase the diagnosis code.
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Q.
Is diagnosis code No. C1041, C1042, C1043 or C1044 set?
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Return to Step 1.
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This diagnosis is complete.
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