Code No. C1242 Longitudinal G sensor signal


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 - CAN Bus Diagnostics Table ).

OPERATION

  • ABS-ECU monitors if the output of G sensor is normal or not.

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

PROBABLE CAUSES

  • Improper installation of the G sensor
  • Malfunction of wheel speed sensor
  • ABS-ECU malfunction
  • External noise interference
  • When the vehicle is driven on a drum roller

DIAGNOSTIC PROCEDURE

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

Q. Is the check result normal?
Go to Step 3.
Repair the CAN bus lines (Refer to GROUP 54C - CAN Bus Diagnostics Table ). On completion, go to Step 2.

STEP 2. Diagnosis code recheck after resetting CAN bus lines

Q. Is the diagnosis code No.C1242 set?
Go to Step 3.
The procedure is complete.

STEP 3. 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 any diagnosis code set?
Troubleshoot for the relevant diagnosis code (Refer to ).
Go to Step 4.

STEP 4. M.U.T.-III data list
Check the following data list (Refer to ).

  • Item 09: G sensor

Q. Is the check result normal?
Go to Step 5.
Replace the hydraulic unit (integrated with ABS-ECU) (Refer to ), and then go to Step 6.

STEP 5. Check whether the diagnosis code is reset.
(1)Erase the diagnosis code.
(2)Drive the vehicle at 20 km/h or higher.
note The ABS warning lamp does not turn OFF in some cases unless the vehicle runs at 20 km/h or higher.

Q. Is the diagnosis code No.C1242 set?
Replace the hydraulic unit (integrated with ABS-ECU) (Refer to ). Then go to Step 6.
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/How to Cope with Intermittent Malfunctions ).

STEP 6. Check whether the diagnosis code is reset.
(1)Erase the diagnosis code.
(2)Drive the vehicle at 20 km/h or higher.
note The ABS warning lamp does not turn OFF in some cases unless the vehicle runs at 20 km/h or higher.

Q. Is the diagnosis code No.C1242 set?
Go to Step 1.
The procedure is complete.