ASC

DTC C1047: FR wheel speed sensor control phase time exceeded

Wheel Speed Sensor Circuit:

CAUTION: If there is any problem in the CAN bus lines, an incorrect diagnostic trouble code may be set. Prior to this diagnosis, diagnose the CAN bus lines.

CIRCUIT 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 diagnostic trouble 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.

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
^ MB991997: ASC check harness

STEP 1. M.U.T.-III CAN bus diagnostics
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. On completion, go to Step 2.

STEP 2. Diagnostic trouble code recheck after resetting CAN bus lines
Q: Is DTC C1047 set?
YES: Go to Step 3.
NO: The procedure is complete.

STEP 3. M.U.T.-III diagnostic trouble code
Check that the diagnostic trouble codes C1015, C101C, C101F, and C1042 are also set.
Q: Are DTC C1015, C101C, C101F, and C1042 also set?
YES: Carry out the diagnosis for the relevant diagnostic trouble codes, and then go to Step 5.
NO: Go to Step 4.

STEP 4. Check whether the diagnostic trouble code is reset.
(1) Erase the diagnostic trouble code.
(2) Drive the vehicle at 12 mph (20 km/h) or more.

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 ASC-ECU, and then go to Step 5.
NO: The procedure is complete.

STEP 5. Check whether the diagnostic trouble code is reset.
(1) Erase the diagnostic trouble code.
(2) Drive the vehicle at 12 mph (20 km/h) or more.

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: Intermittent malfunction.
NO: The procedure is complete.