C1047
DTC C1047: FR wheel speed sensor control phase time exceeded
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 Initial Inspection and Diagnostic Overview ).
- Whenever the ECU is replaced, ensure that the CAN bus lines are normal.
- When the hydraulic unit (integrated with ASC-ECU) is replaced, always perform the calibration of steering wheel sensor, G and yaw rate sensor, brake fluid pressure sensor, cut valve, and inlet valve (Refer to G and Yaw Rate Sensor Calibration , Testing and Inspection , Master Cylinder Brake Fluid Pressure Sensor Calibration , and Testing and Inspection ).
CIRCUIT OPERATION
- Each wheel speed detecting section is a kind of a pulse generator. It consists of the encoder (plate on which the north and south pole of magnet are arranged alternately) for detecting the wheel speed, which rotates at the same speed of the wheels, and the wheel speed sensor. This detecting section outputs the frequency pulse signals in proportion to the wheel speed.
- The pulse signals generated by the wheel speed detecting section are sent to ASC-ECU. ASC-ECU uses the frequency of the pulse signals to determine the wheel speed.
DTC SET CONDITIONS
This diagnostic trouble code is set if any malfunction below is detected.
- When the brake fluid pressure is decreased for a long time.
- When the brake fluid pressure is held for a long time.
NOTE:
ABS controls the vehicle based on the wheel speed signal. When the brake fluid pressure is decreased or held for an abnormally long time, the wheel speed sensor signal may have a problem.
PROBABLE CAUSES
- 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 wheel speed detection encoder
- Adhesion of foreign materials on the wheel speed sensor
- Adhesion of foreign materials on the wheel speed detection encoder
- Wheel bearing malfunction
- Improper installation of the wheel speed sensor
- Deformation of the wheel speed detection encoder
- Disturbance of magnetization pattern for wheel speed detection encoder
- Missing teeth of the wheel speed detection encoder
DIAGNOSIS
Required Special Tools:
- MB991958 Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: Vehicle Communication Interface (V.C.I.)
- MB991827 M.U.T.-III USB Cable
- MB991910 M.U.T.-III Main Harness A
STEP 1. Using scan tool MB991958, diagnose the CAN bus lines.
Use scan tool to diagnose the CAN bus lines.
Q. Is the check result normal?
YES Go to Step 3.
NO Repair the CAN bus lines CAN Bus Diagnostics Chart).
On completion, go to Step 2.
STEP 2. DTC recheck after resetting CAN bus lines
Q. Is DTC C1047 set?
YES Go to Step 3.
NO The procedure is complete.
STEP 3. Using scan tool MB991958, check the DTC
Check that the DTC C1015, C101C, C101F, or C1042 is also set.
Q. Is the DTC C1015, C101C, C101F, or C1042 also set?
YES Carry out the diagnosis for the relevant DTC.
NO Go to Step 4.
STEP 4. Using scan tool MB991958, check the data list
Check the following data list (Refer to Data List Reference Table).
- Item No.02: FR wheel speed sensor
Q. Is the check result normal?
YES Go to Step 11.
NO Go to Step 5.
STEP 5. Connector check: A-05 ASC-ECU connector, A-03 front wheel speed sensor [RH] connector
Q. Is the check result normal?
YES Go to Step 6.
NO Repair the defective connector. Then go to Step 13.
STEP 6. Wiring harness check between A-05 ASC-ECU connector terminal No. 34 and A-03 front wheel speed sensor [RH] connector terminal No. 1, and between A-05 ASC-ECU connector terminal No. 33 and A-03 front wheel speed sensor [RH] connector terminal No. 2
Q. Is the check result normal?
YES Go to Step 7.
NO Repair the wiring harness. Then go to Step 13.
STEP 7. Check for wheel speed sensor [FR] installation
Check how the wheel speed sensor [FR] is installed (Disconnection of wheel speed sensor [FR], loose mounting bolt, etc.).
Q. Is the check result normal?
YES Go to Step 8.
NO Reinstall the wheel speed sensor [FR] correctly (Refer to Service and Repair).
Then go to Step 8.
STEP 8. Check for wheel speed sensor [FR] output current
Refer to Wheel Speed Sensor Output Current Measurement.
Q. Is the check result normal?
YES Go to Step 9.
NO Replace the wheel speed sensor [FR] (Refer to Service and Repair).
Then go to Step 12.
STEP 9. Check for wheel bearing looseness
NOTE:
- Loose wheel bearing may increase the gap between the wheel speed sensor[ FR] and the wheel speed detection magnet encoder.
- Check the wheel bearing[ FR] for looseness Front Axle ).
Q. Is the check result normal?
YES Go to Step 10.
NO Replace the front hub assembly [FR] Front Axle Hub Assembly Removal and Installation [Flange Nut Type]). Then go to Step 13.
STEP 10. Check of wheel speed detection encoder
Check the encoder for adhesion of foreign materials or deformation.
Q. Is the check result normal?
YES Go to Step 11.
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.
Then go to Step 13.
NO (Deformation) : Replace the front hub assembly [FR] Front Axle Hub Assembly Removal and Installation [Flange Nut Type]). Then go to Step 13.
STEP 11. Check whether the DTC is reset.
(1)Erase the DTC.
(2)Drive the vehicle at 12mph (20 km/h) or higher.
NOTE:
The ABS warning light does not turn OFF in some cases unless the vehicle runs at 12mph
(20 km/h) or higher.
Q. Is DTC C1047 set?
YES Replace the wheel speed sensor [FR] (Refer to Service and Repair). Then go to Step 12.
NO Intermittent malfunction How to Cope With Intermittent Malfunctions).
STEP 12. Check whether the DTC is reset.
(1)Erase the DTC.
(2)Drive the vehicle at 12 mph (20 km/h) or higher.
NOTE:
The ABS warning light does not turn OFF in some cases unless the vehicle runs at 12 mph
(20 km/h) or higher.
Q. Is DTC C1047 set?
YES Replace the hydraulic unit (integrated with ASC-ECU) (Refer to Service and Repair).
Then go to Step 13.
NO The procedure is complete.
STEP 13. Check whether the DTC is reset.
(1)Erase the DTC.
(2)Drive the vehicle at 12 mph (20 km/h) or higher.
NOTE:
The ABS warning light does not turn OFF in some cases unless the vehicle runs at 12 mph
(20 km/h) or higher.
Q. Is DTC C1047 set?
YES Return to Step 1.
NO The procedure is complete.