U0125

DTC U0125 G and yaw rate sensor message time-out error/message error











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 Diagnostic trouble code diagnosis Diagnostic Trouble Code Descriptions).
^ Whenever ECU is replaced, ensure that the CAN bus lines are normal.
^ Do not drop or shock the G and yaw rate sensor.
^ When the G and yaw rate sensor is replaced, always carry out calibration to make ASC-ECU learn the neutral point.
^ When the hydraulic unit (integrated with ASC-ECU) is replaced, always carry out the calibration of the steering wheel sensor, the G and yaw rate sensor and brake fluid pressure sensor.

OPERATION
The G and yaw rate sensor outputs the signal to ASC-ECU via the special CAN bus lines.

DTC SET CONDITIONS
This DTC is set when the ASC-ECU cannot receive the signal from the G and yaw rate sensor although there is no abnormality in ASC-ECU supply voltage.

NOTE: When an abnormality is present in the ASC-ECU supply voltage, DTC C2100 (low voltage error) is set, and DTC U0125 is not set.

PROBABLE CAUSES
^ Wiring harness or connector failure for the special CAN bus lines between ASC-ECU and the G and yaw rate sensor
^ G and yaw rate sensor malfunction
^ ASC-ECU malfunction
^ External noise interference

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 M.U.T.-III to diagnose the CAN bus lines.
Q: Is the check result normal?
YES: Go to Step 3.
NO: Repair the CAN bus lines. (Refer to Diagnosis - CAN Bus Diagnostic Table CAN Bus Diagnostics Table.) On completion, go to Step 2.

STEP 2. DTC recheck after resetting CAN bus lines
Q: Is DTC U0125 set?
YES: Go to Step 3.
NO: The procedure is complete.

STEP 3. Connector check: A-51 ASC-ECU connector, C-137 G and yaw rate sensor connector
Q: Is the check result normal?
YES: Go to Step 4.
NO: Repair the connector, and then go to Step 7.

STEP 4. Wiring harness check between A-51 ASC-ECU connector terminal No.18 and C-137 G and yaw rate sensor connector terminal No.2 as well as between A-51 ASC-ECU connector terminal No.19 and C-137 G and yaw rate sensor connector terminal No.3
^ Check the communication circuit for open and short circuit.
Q: Is the check result normal?
YES: Go to Step 5.
NO: Repair the wiring harness, and then go to Step 7.

STEP 5. DTC recheck
Q: Is DTC U0125 set?
YES: Replace the G and yaw rate sensor. Then go to Step 6.
NO: Intermittent malfunction.

STEP 6. DTC recheck
Q: Is DTC U0125 set?
YES: Replace the hydraulic unit (ASC-ECU). Then go to Step 7.
NO: The procedure is complete.

STEP 7. DTC recheck
Q: Is DTC U0125 set?
YES: Return to Step 1.
NO: The procedure is complete.