Code No.C1201: Front Right Wheel Speed Sensor
Code No.C1206: Front Left wheel Speed Sensor
Code No.C1211: Rear Right wheel Speed Sensor
Code No.C1216: Rear Left wheel Speed Sensor



caution If there is any problem in the CAN bus lines, an incorrect diagnosis code may be set. Diagnose the CAN bus lines before the diagnosis codes (Refer to GROUP 54F, CAN bus-line diagnostic flow ).

OPERATION



DIAGNOSIS CODE SET CONDITIONS


The ABS-ECU monitors the signals from each wheel speed sensor while the vehicle is being driven. If any faults below are found in these sensor signals, the ECU will set the relevant diagnosis code.

PROBABLE CAUSES


The most likely causes for these diagnosis codes to set are:

DIAGNOSIS

STEP 1. M.U.T.-III CAN bus diagnostics

caution Before connecting or disconnecting the M.U.T.-III, turn the ignition switch to the "LOCK" (OFF) position.
(1)Connect M.U.T.-III to the 16-pin diagnosis connector.
(2)Turn the ignition switch to the "ON" position.
(3)Diagnose the CAN bus line.
(4)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is the check result normal?

Go to Step 3

Repair the CAN bus line (Refer to GROUP 54F, CAN bus line Diagnostic flow ). Then go to Step 2.

STEP 2. Check whether the diagnosis code is reset.

caution Before connecting or disconnecting the M.U.T.-III, turn the ignition switch to the "LOCK" (OFF) position.
(1)Turn the ignition switch to the "ON" position.
(2)Erase the diagnosis code.
(3)Turn the ignition switch to the "LOCK" (OFF) position.
(4)Turn the ignition switch to the "ON" position.
(5)Check if the diagnosis code is set.
(6)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is code No.C1201, C1206, C1211 and C1216 set?

Go to Step 3.

The procedure is complete.

STEP 3. Check whether the diagnosis code is reset.

caution Before connecting or disconnecting the M.U.T.-III, turn the ignition switch to the "LOCK" (OFF) position.
Use M.U.T.-III to check whether diagnosis codes No.C1200, C1205, C1210 and C1215 have been set simultaneously.
(1)Connect M.U.T.-III to the 16-pin diagnosis connector.
(2)Turn the ignition switch to the "ON" position.
(3)Check whether diagnosis codes No.C1200, C1205, C1210 or C1215 have been set.
(4)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is codes No.C1200, C1205, C1210 or C1215 set?

Carry out diagnosis relevant to diagnosis codes No.C1200, C1205, C1210 or C1215 (Refer to ).

Go to Step 4.

STEP 4. Check the installation condition of the wheel speed sensors.
For the wheel speed sensor, which the diagnosis code indicates, check whether the sensor or its mounting bolts are loosened.

  • Code No.C1201 is set: Front right wheel speed sensor
  • Code No.C1206 is set: Front left wheel speed sensor
  • Code No.C1211 is set: Rear right wheel speed sensor
  • Code No.C1216 is set: Rear left wheel speed sensor

Q. Is the check result normal?
Go to Step 5.
Reinstall the wheel speed sensor correctly. Then go to Step 15.

STEP 5. Check the wheel speed sensor after it is removed from the vehicle.
Check the wheel speed sensor, which the diagnosis code indicates (Refer to ).

  • Code No.C1201 is set: Front right wheel speed sensor
  • Code No.C1206 is set: Front left wheel speed sensor
  • Code No.C1211 is set: Rear right wheel speed sensor
  • Code No.C1216 is set: Rear left wheel speed sensor

Q. Is the check result normal?
Go to Step 6.
Replace the wheel speed sensor. Then go to Step 15.

STEP 6. Check the wheel bearing for looseness.
note If the wheel bearing is loose, the gap between the wheel speed sensor and rotor may become excessive. Check the wheel bearing, which diagnosis code indicates, for looseness.

  • Code No.C1201 is set: Check the front right wheel bearing (Refer to GROUP 26, On-vehicle service - Hub axial play check ).
  • Code No.C1206 is set: Check the front left wheel bearing (Refer to GROUP 26, On-vehicle service - Hub axial play check ).
  • Code No.C1211 is set: Check the rear right wheel bearing (Refer to GROUP 27, On-vehicle service - Wheel bearing axial play check ).
  • Code No.C1216 is set: Check the rear left wheel bearing (Refer to GROUP 27, On-vehicle service - Wheel bearing axial play check ).

Q. Is the check result normal?
Go to Step 7.
NO (front hub axial play is not within the standard value) : Replace the front hub assembly (Refer to GROUP 26, Front axle hub assembly ). Then go to Step 15.
NO (rear wheel bearing axial play is not within the standard value) : Replace the rear hub assembly (Refer to GROUP 27, Rear axle hub assembly ). Then go to Step 15.

STEP 7. Check the vehicle speed detection encoder.
Check the vehicle speed detection encoder, which diagnosis code indicates, for foreign material or deformation.

  • Code No.C1201 is set: Front right wheel speed sensor
  • Code No.C1206 is set: Front left wheel speed sensor
  • Code No.C1211 is set: Rear right wheel speed sensor
  • Code No.C1216 is set: Rear left wheel speed sensor

Q. Is the check result normal?
Go to Step 8.
NO (front hub axial play is not within the standard value) : If the vehicle speed detection encoder is contaminated with foreign material, clean it. If the front hub assembly is deformed, replace it (Refer to GROUP 26, Front axle hub assembly ). Then go to Step 15.
NO (rear wheel bearing axial play is not within the standard value) : If the vehicle speed detection encoder is contaminated with foreign material, clean it. If the rear axle hub assembly is deformed, replace it (Refer to GROUP 27, Rear axle hub assembly ). Then go to Step 15.

STEP 8. Voltage measurement at ABS-ECU connector A-03.

(1)Disconnect the connector A-03, and connect special tool ABS Check Harness (MB991974) to the wiring harness-side connector.
note Do not connect special tool ABS Check Harness (MB991974) to the ABS-ECU.
(2)Turn the ignition switch to the "ON" position.
(3)Measure the voltage between the relevant signal and earth terminals in the wheel speed sensor circuit and body earth.
OK: Less than 1V

  • Code No.C1201 is set: Between signal terminal 5 and body earth, and between earth terminal 6 and body earth
  • Code No.C1206 is set: Between signal terminal 8 and body earth, and between earth terminal 9 and body earth
  • Code No.C1211 is set: Between signal terminal 11 and body earth, and between earth terminal 12 and body earth
  • Code No.C1216 is set: Between signal terminal 2 and body earth, and between earth terminal 3 and body earth

Q. Is the check result normal?

Go to Step 9.

NO (When the voltage between terminal 5 or 6 - and body earth measures more than 1 V) : Go to Step 10.

NO (When the voltage between terminal 8 or 9 - and body earth measures more than 1 V) : Go to Step 11.

NO (When the voltage between terminal 11 or 12 - and body earth measures more than 1 V) : Go to Step 12.

NO (When the voltage between terminal 2 or 3 - and body earth measures more than 1 V) : Go to Step 13.

STEP 9. Resistance measurement at ABS-ECU connector A-03.

(1)Disconnect the connector A-03, and connect special tool ABS Check Harness (MB991974) to the wiring harness-side connector.
note Do not connect special tool ABS Check Harness (MB991974) to the ABS-ECU.
(2)Measure the resistance between the relevant signal and earth terminals in the wheel speed sensor circuit and body earth.
OK: No continuity

  • Code No.C1201 is set: Between signal terminal 5 and body earth, and between earth terminal 6 and body earth
  • Code No.C1206 is set: Between signal terminal 8 and body earth, and between earth terminal 9 and body earth
  • Code No.C1211 is set: Between signal terminal 11 and body earth, and between earth terminal 12 and body earth
  • Code No.C1216 is set: Between signal terminal 2 and body earth, and between earth terminal 3 and body earth

Q. Is the check result normal?

YES (Continuity exists between terminal 5 or terminal 6 and body earth) : Go to Step 10.

YES (Continuity exists between terminal 8 or terminal 9 and body earth) : Go to Step 11.

YES (Continuity exists between terminal 11 or terminal 12 and body earth) : Go to Step 12.

YES (Continuity exists between terminal 2 or terminal 3 and body earth) : Go to Step 13.

Go to Step 14.

STEP 10. Check ABS-ECU connector A-03 and wheel speed sensor <front: RH> connector A-02 for loose, corroded or damaged terminals, or terminals pushed back in the connector.




Q. Is the check result normal?

Open or short circuit may be present in the front right wheel speed sensor circuit. Repair the wiring harness between ABS-ECU connector A-03 (terminals 5 and 6) and front right wheel speed sensor A-02 (terminals 1 and 2). Then go to Step 15.

Repair or replace the damaged component(s). Then go to Step 15.

STEP 11. Check ABS-ECU connector A-03 and wheel speed sensor <front: LH> connector A-05 for loose, corroded or damaged terminals, or terminals pushed back in the connector.




Q. Is the check result normal?

Open or short circuit may be present in the front right wheel speed sensor circuit. Repair the wiring harness between ABS-ECU connector A-03 (terminals 8 and 9) and front left wheel speed sensor A-05 (terminals 2 and 1). Then go to Step 15.

Repair or replace the damaged component(s). Then go to Step 15.

STEP 12. Check ABS-ECU connector A-03, intermediate connector C-16, C-124, D-28 and wheel speed sensor <rear: RH> connector D-06 for loose, corroded or damaged terminals, or terminals pushed back in the connector.







Q. Is the check result normal?

Open or short circuit may be present in the rear right wheel speed sensor circuit. Repair the wiring harness between ABS-ECU connector A-03 (terminals 11 and 12) and rear right wheel speed sensor D-06 (terminals 1 and 2). Then go to Step 15.

Repair or replace the damaged component(s). Then go to Step 15.

STEP 13. Check ABS-ECU connector A-03, intermediate connector C-16, C-124, D-28 and wheel speed sensor <rear: LH> connector D-14 for loose, corroded or damaged terminals, or terminals pushed back in the connector.







Q. Is the check result normal?

Open or short circuit may be present in the rear left wheel speed sensor circuit. Repair the wiring harness between ABS-ECU connector A-03 (terminals 2 and 3) and rear left wheel speed sensor D-14 (terminals 2 and 1). Then go to Step 15.

Repair or replace the damaged component(s). Then go to Step 15.

STEP 14. Check whether the diagnosis code is reset.

Check again if the diagnosis code is set.
(1)Turn the ignition switch to the "ON" position.
(2)Erase the diagnosis code.
(3)Turn the ignition switch to the "LOCK" (OFF) position.
(4)Turn the ignition switch to the "ON" position.
(5)Check if the diagnosis code is set.
(6)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is code No.C1201, C1206, C1211 or C1216 set?

Replace the hydraulic unit (integrated with ABS-ECU). Then go to Step 15.

It can be assumed that this malfunction is intermittent. Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction .

STEP 15. Check whether the diagnosis code is reset.

Check again if the diagnosis code is set.
(1)Turn the ignition switch to the "ON" position.
(2)Erase the diagnosis code.
(3)Turn the ignition switch to the "LOCK" (OFF) position.
(4)Turn the ignition switch to the "ON" position.
(5)Check if the diagnosis code is set.
(6)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is code No.C1201, C1206, C1211 or C1216 set?

Go to Step 1.

The procedure is complete.