Code No. C1242 Abnormality in G and yaw rate sensor (Abnormality in longitudinal G sensor output signal) <4WD>


caution
  • If there is any problem in the CAN bus lines, an incorrect diagnosis code may be set. Prior to this diagnosis, diagnose the CAN bus lines (Refer to GROUP 54C, Trouble code diagnosis ).
  • 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 (Refer to ).
  • 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 (Refer to , and ).

OPERATION
ABS-ECU monitors if the output of G and yaw rate sensor is normal or not.

DIAGNOSIS CODE SET CONDITIONS
This diagnosis code is set when the abnormality is detected by comparing the longitudinal G-sensor value output from the G and yaw rate sensor with the value output from the wheel speed sensor.

PROBABLE CAUSES

  • Improper installation of the G and yaw rate sensor
  • G and yaw rate sensor malfunction
  • Malfunction of wheel speed sensor
  • ASC-ECU malfunction
  • External noise interference
note When rotated on the four-wheel drum tester, this diagnosis code may be set.

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III CAN bus diagnosis
Use M.U.T.-III to diagnose the CAN bus lines.

Q. Is the check result normal?
Go to Step 2.
Repair the CAN bus lines (Refer to GROUP 54C - CAN Bus Diagnosis table ). On completion, go to Step 2.

STEP 2. M.U.T.-III diagnosis code
Check that the diagnosis code U0125 is set in ASC-ECU.

Q. Is the diagnosis code No.U0125 set?
Troubleshoot for the diagnosis code (Refer to ). Then go to Step 3.
Go to Step 3.

STEP 3. Diagnosis code recheck after resetting CAN bus lines

Q. Is the diagnosis code No.C1242 set?
Go to Step 4.
This diagnosis is complete.

STEP 4. Check the wheel speed sensor-related diagnosis code.
Use the M.U.T.-III to check whether the wheel speed sensor-related diagnosis code is set or not.

Q. Is the diagnosis code set?
Troubleshoot for the relevant diagnosis code (Refer to ).
Go to Step 5.

STEP 5. G and yaw rate sensor check
Check that the G and yaw rate sensor is installed correctly.

Q. Is the check result normal?
After checking the G and yaw rate sensor, carry out calibration of the G and yaw rate sensor to make ASC-ECU relearn the neutral point. (Refer to .) Then go to Step 6.
Reinstall the G and yaw rate sensor correctly (Refer to ), and then go to Step 8.

STEP 6. M.U.T.-III data list
Check the following service data (Refer to ).

  • Item 09: G sensor

Q. Is the check result normal?
Go to Step 7.
Replace the G and yaw rate sensor (Refer to ), and then go to Step 7.

STEP 7. Check whether the diagnosis code is reset.

Q. Is the diagnosis code No.C1242 set?
Replace the hydraulic unit (ASC-ECU) (Refer to ), and then go to Step 8.
Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).

STEP 8. Check whether the diagnosis code is reset.

Q. Is the diagnosis code No.C1242 set?
Return to Step 1.
This diagnosis is complete.