Code No.C1242: G and yaw rate sensor failure <Straight G sensor output value abnormal>

caution

If there is any problem in the CAN bus lines, an incorrect diagnosis code may be stored. Prior to this diagnosis, diagnose the CAN bus lines.
Whenever the ECU is replaced, ensure that the CAN bus lines are normal.
When the hydraulic unit (integrated with ASC-ECU) is replaced, after turning the ignition switch ON or OFF (vehicle information from ETACS-ECU is registered), always carry out the calibration of the steering wheel sensor, the G and yaw rate sensor, and brake fluid pressure sensor.(Refer to GROUP 35C - On-vehicle Service , and .)

OPERATION

The G&yaw rate sensor, which is integrated in the ASC-ECU, sends a signal to the 4WD-ECU via CAN bus lines.

DIAGNOSIS CODE SET CONDITIONS

This diagnosis code is stored when the abnormality below is detected:

Abnormality in G and yaw rate sensor output value
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

Malfunction of G and yaw rate sensor
Malfunction of wheel speed sensor
Malfunction of stop lamp switch
Malfunction of 4WD-ECU

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III CAN bus diagnostics.

Use M.U.T.-III to perform the CAN bus diagnosis.

Q. Is the check result normal?

	Go to Step 3

	Repair the CAN bus lines (Refer to GROUP 54C - Troubleshooting ). After repairing the CAN bus line, go to Step 2.

STEP 2. Check whether the diagnosis code is stored again.

Q. Is diagnosis code No.C1242 stored?

	Go to Step 3

	This diagnosis is complete.

STEP 3. M.U.T.-III other system diagnosis code.

Use M.U.T.-III to check whether the diagnosis code is stored in the ASC-ECU. (Refer to GROUP 35C - Troubleshooting

Q. Is the diagnosis code stored?

	Perform the relevant troubleshooting. (Refer to GROUP 35C - Troubleshooting .)

	Go to Step 4

STEP 4. M.U.T.-III other system diagnosis code.

Check if the wheel speed sensor-related diagnosis code is stored.

Q. Is the diagnosis code stored?

	Perform the relevant troubleshooting.

	Go to Step 5

STEP 5. Check of hydraulic unit (integrated with G and yaw rate sensor) installation status.

Check that the hydraulic unit (integrated with G and yaw rate sensor) is installed correctly (Refer to GROUP 35B - Hydraulic unit (integrated with G and yaw rate sensor)

<Vehicles with ABS>GROUP 35C - Hydraulic unit (integrated with G and yaw rate sensor)

<Vehicles with ASC>).

Q. Is the check result normal?

	Go to Step 6

	Reinstall the hydraulic unit (integrated with G and yaw rate sensor) correctly. Then go to Step 6.

STEP 6. M.U.T.-III data list.

Check the following data list (Refer to

Item No.24: Longitudinal G sensor

Q. Is the check result normal?

	Go to Step 7

	Replace the hydraulic unit (integrated with G and yaw rate sensor) (Refer to GROUP 35B - Hydraulic unit (integrated with G and yaw rate sensor) <Vehicles with ABS> or GROUP 35C - Hydraulic unit (integrated with G and yaw rate sensor) <Vehicles with ASC>). Then go to Step 8.

STEP 7. Check whether the diagnosis code is stored again.

Q. Is diagnosis code No.C1242 stored?

	Replace the 4WD-ECU (Refer to ). 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 stored again.

Q. Is diagnosis code No.C1242 stored?

	Return to Step 1.

	This diagnosis is complete.