|
- 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.
|
|
This diagnosis code is set if any malfunction below is found:
|
|
- When the brake fluid pressure is decreased for a long time.
- When the brake fluid pressure is held for a long time.
|
|
- Damaged wiring harness and connectors
- External noise interference
- Malfunction of wheel speed sensor
- ABS-ECU malfunction
- Excessive gap between the wheel speed sensor and 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
- Wheel bearing malfunction
- Improper installation of the wheel speed sensor
- Deformation of the magnetic encoder for wheel speed detection
- Disturbance of magnetization pattern for magnetic encoder for wheel speed detection
- Missing teeth of the magnetic encoder for wheel speed detection
|
|
Use M.U.T.-III to diagnose the CAN bus lines.
|
|
Q.
Is the check result normal?
|
|
Repair the CAN bus lines (Refer to GROUP 54C - CAN Bus Diagnosis table ). On completion, go to Step 2.
|
|
|
|
Q.
Is the diagnosis code No. C1046 set?
|
|
This diagnosis is complete.
|
|
|
|
Check that the diagnosis codes No. C100A, C1011, C1014, and C1041 are also set.
|
|
Q.
Are the diagnosis codes No. C100A, C1011, C1014, and C1041 also set?
|
|
Carry out the diagnosis for the relevant diagnosis codes, and then go to Step 16.
|
|
|
|
Check the following service data (Refer to ).
|
|
- Item No.01: FL wheel speed sensor
|
|
Q.
Is the check result normal?
|
|
(1)Disconnect the ABS-ECU connector, connect special tool ABS check harness (MB991974) to the harness-side connector, and then measure the voltage at the special tool connector side.
note |
Do not connect the special tool ABS check harness (MB991974) to ABS-ECU.
|
(2)Turn the ignition switch to the ON position. (3)Measure the voltage between the wheel speed sensor power supply terminal (signal terminal) No.18 and the body earth, and between the wheel speed sensor earth terminal No.19 and the body earth. OK: 1 volt or less
Q.
Is the check result normal?
Go to Step 6.
NO (Not normal at the terminal No.18 or 19) : Go to Step 7.
|
|
(1)Disconnect the ABS-ECU connector, connect special tool ABS check harness (MB991974) to the harness-side connector, and then measure the resistance at the special tool connector side.
note |
Do not connect the special tool ABS check harness (MB991974) to ABS-ECU.
|
(2)Resistance between the wheel speed sensor power supply terminal (signal terminal) No.18 and the body earth, and between the wheel speed sensor earth terminal No.19 and the body earth. OK: No continuity
Q.
Is the check result normal?
Go to Step 9.
NO (Not normal at the terminal No.18 or 19) : Go to Step 7.
|
|
Q.
Is the check result normal?
|
|
Repair the defective connector.
|
|
|
|
- Check for short circuit in wheel speed sensor <FL> circuit
|
|
Q.
Is the check result normal?
|
|
Replace the wheel speed sensor <FL> (Refer to ).
|
|
|
|
Repair the wiring harness.
|
|
|
|
(1)Disconnect the ABS-ECU connector, connect special tool ABS check harness (MB991974) to the ABS-ECU-side connector and harness-side connector, and then measure the voltage at the special tool connector side. (2)Turn the ignition switch to the ON position. (3)Measure the voltage between the wheel speed sensor circuit power supply terminal (signal terminal) No.18 and the body earth. OK: System voltage
Q.
Is the check result normal?
Go to Step 10.
Go to Step 12.
|
|
- Check for open circuit in wheel speed sensor <FL> circuit.
|
|
Q.
Is the check result normal?
|
|
Repair the wiring harness.
|
|
|
|
Q.
Is the check result normal?
|
|
Replace the wheel speed sensor <FL> (Refer to ).
|
|
|
|
Q.
Is the check result normal?
|
|
Repair the defective connector.
|
|
|
|
Check how the wheel speed sensor <FL> is installed (Disconnection of wheel speed sensor, loose mounting bolt, etc.).
|
|
Q.
Is the check result normal?
|
|
Reinstall the wheel speed sensor <FL> correctly (Refer to ).
|
|
|
|
Q.
Is the check result normal?
|
|
Replace the wheel bearing (Refer to GROUP 26 - Front axle hub assembly ).
|
|
|
|
Check the encoder for adhesion of foreign materials or deformation.
Q.
Is the check result normal?
Go to Step 16.
NO (Adhesion of foreign materials) : 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.
NO (Deformation) : Replace the wheel bearing (Refer to GROUP 26 - Front axle hub assembly ).
|
|
(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. C1046 set?
|
|
Replace the ABS-ECU (Refer to ).
|
|
|
|
This diagnosis is complete.
|
|
|