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DTC C1046 FL wheel speed sensor phase
DTC C1047 FR wheel speed sensor phase
DTC C1048 RL wheel speed sensor phase
DTC C1049 RR wheel speed sensor phase
 
 
caution
  • If there is any problem in the CAN bus lines, an incorrect DTC 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.
 
 
 
DTC SET CONDITIONS
This DTC 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.
 
 
 
TROUBLESHOOTING HINTS
  • Damaged wiring harness and connectors
  • External noise interference
  • Malfunction of wheel speed sensor
  • ASC-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
 
 
 
 
DIAGNOSIS
Required Special Tools:
  • MB991223: Harness Set
  • MB992006: Extra Fine Probe
STEP 1. Scan tool (M.U.T.-IIISE) CAN bus diagnosis.
(1)
cautionTo prevent damage to scan tool (M.U.T.-IIISE), always turn off the power supply mode of the electric motor switch before connecting or disconnecting scan tool (M.U.T.-IIISE).
Connect scan tool (M.U.T.-IIISE). Refer to "How to connect the Scan Tool (M.U.T.-IIISE) ."
(2) Turn on the power supply mode of the electric motor switch.
(3) Diagnose the CAN bus line.
(4) Turn off the power supply mode of the electric motor switch.
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. DTC recheck after resetting CAN bus lines.
Is DTC No.C1046, C1047, C1048 or C1049 set?
Go to Step 3.
This diagnosis is complete.
 
STEP 3. Check whether the DTC is set again.
DTC C1046 is set
  • Check that the DTCs No.C100A, C1011, C1014, and C1041 are also set.
DTC C1047 is set
  • Check that the DTCs No.C1015, C101C, C101F, and C1042 are also set.
DTC C1048 is set
  • Check that the DTCs No.C1020, C1027, C102A, and C1043 are also set.
DTC C1049 is set
  • Check that the DTCs No.C102B, C1032, C1035, and C1044 are also set.
Are the DTCs set?
Carry out the diagnosis for the relevant DTCs.
Go to Step 4.
 
STEP 4. Scan tool (M.U.T.-IIISE) data list.
Check the following data list (Refer to ).
  • Item No. 01: FL wheel speed sensor
  • Item No. 02: FR wheel speed sensor
  • Item No. 03: RL wheel speed sensor
  • Item No. 04: RR wheel speed sensor
Is the check result normal?
Go to Step 10.
Go to Step 5.
 
STEP 5. Check the wiring harness between the ASC-ECU connector terminal and the wheel speed sensor connector terminal.
DTC C1046 is set
  • Check of short to power supply, short to ground, and open circuit in FL+, FL- line between ASC-ECU connector and front wheel speed sensor (LH) connector.
DTC C1047 is set
  • Check of short to power supply, short to ground, and open circuit in FR+, FR- line between ASC-ECU connector and front wheel speed sensor (RH) connector.
DTC C1048 is set
  • Check of short to power supply, short to ground, and open circuit in RL+, RL- line between ASC-ECU connector and rear wheel speed sensor (LH) connector.
DTC C1049 is set
  • Check of short to power supply, short to ground, and open circuit in RR+, RR- line between ASC-ECU connector and rear wheel speed sensor (RH) connector.
Is the check result normal?
Go to Step 6.
Repair the connector(s) or wiring harness. Then go to Step 12.
 
STEP 6. Check for wheel speed sensor installation.
Check how the wheel speed sensor is installed (Disconnection of wheel speed sensor, loose mounting bolt, etc.).
Is the check result normal?
Go to Step 7.
Reinstall the wheel speed sensor correctly (Refer to <front> or <rear>). Then go to Step 7.
 
STEP 7. Check for wheel speed sensor output current.
Refer to .
Is the check result normal?
Go to Step 8.
Replace the wheel speed sensor (Refer to <front> or <rear>). Then go to Step 11.
 
STEP 8. Check for wheel bearing looseness.
noteLoose 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 End Play Check <front>, GROUP 27 - Wheel Bearing End Play Check <rear>).
Is the check result normal?
Go to Step 9.
Replace the wheel bearing (front) or rear wheel hub assembly (rear) (Refer to GROUP 26 - Front Axle Hub Assembly <front>, GROUP 27 - Rear Axle Hub Assembly <rear>). Then go to Step 12.
 
STEP 9. Check of wheel speed detection encoder.
Check the encoder for adhesion of foreign materials or deformation.
Is the check result normal?
Go to Step 10.
: 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. Then go to Step 12.
: Replace the wheel bearing (front) or rear wheel hub assembly (rear) (Refer to GROUP 26 - Front Axle Hub Assembly <front>, GROUP 27 - Rear Axle Hub Assembly <rear>). Then go to Step 12 .
 
STEP 10. Check whether the DTC is set again.
(1) Erase the DTC.
(2) Drive the vehicle at 12 mph (20 km/h) or higher.
noteThe ABS warning light does not turn OFF in some cases unless the vehicle runs at 12 mph (20 km/h) or higher.
Is DTC No.C1046, C1047, C1048 or C1049 set?
Replace the wheel speed sensor (Refer to <front> or <rear>). Then go to Step 11.
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/How to Cope with Intermittent Malfunctions ).
 
STEP 11. Check whether the DTC is set again.
(1) Erase the DTC.
(2) Drive the vehicle at 12 mph (20 km/h) or higher.
noteThe ABS warning light does not turn OFF in some cases unless the vehicle runs at 12 mph (20 km/h) or higher.
Is DTC No.C1046, C1047, C1048 or C1049 set?
Replace the hydraulic unit (integrated with ASC-ECU) (Refer to ). Then go to Step 12.
This diagnosis is complete.
 
STEP 12. Check whether the DTC is set again.
(1) Erase the DTC.
(2) Drive the vehicle at 12 mph (20 km/h) or higher.
noteThe ABS warning light does not turn OFF in some cases unless the vehicle runs at 12 mph (20 km/h) or higher.
Is DTC No.C1046, C1047, C1048 or C1049 set?
Return to Step 1.
This diagnosis is complete.