[Previous][Next]
DTC C1242: Longitudinal G sensor signal
 
 
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 GROUP 54C, Trouble code diagnosis ).
  • Whenever ECU is replaced, ensure that the CAN bus lines are normal.
 
 
OPERATION
ASC-ECU monitors if the output of G and yaw rate sensor is normal or not.
 
 
 
DTC SET CONDITIONS
This DTC 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
  • Malfunction of wheel speed sensor
  • ASC-ECU malfunction
  • External noise interference
noteWhen rotated on the four-wheel drum tester, this DTC may be set.
 
 
 
 
DIAGNOSIS
STEP 1. Using scan tool MB991958, diagnose the CAN bus lines.
Use scan tool MB991958 to diagnose the CAN bus lines.
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. DTC recheck after resetting CAN bus lines
Is DTC No.C1242 set?
Go to Step 3.
This diagnosis is complete.
 
STEP 3. Check the wheel speed sensor-related DTC.
Use the scan tool MB991958 to check whether the wheel speed sensor-related DTC is set or not.
Is the DTC set?
Troubleshoot for the relevant DTC (Refer to ).
Go to Step 4.
 
STEP 4. Check whether the ASC-ECU is installed properly.
Check whether the ASC-ECU is installed correctly (Refer to ).
Is the check result normal?
Execute "G sensor calibration" on "Special function". After the calibration is performed (Refer to ), turn the ignition switch from "OFF" to "ON". Then go to Step 5.
Install the ASC-ECU properly, and execute "G sensor calibration" on "Special function". After the calibration is performed (Refer to ), turn the ignition switch from "OFF" to "ON". Then go to Step 5.
 
STEP 5. Scan tool MB991958 data list
Check the following data list under curb weight condition or one occupant (driver) only in the vehicle, on a flat road (Refer to ).
  • Item 09: G Sensor
  • Item 17: G sensor offset
Is the check result normal?
Turn the ignition switch to the "ON" from "OFF" position. Then go to Step 6.
Replace the hydraulic unit (integrated with ASC-ECU) (Refer to ), and then go to Step 7.
 
STEP 6. Check whether the DTC is set again.
(1) Erase the DTC.
(2) Drive the vehicle at 20 km/h (12 mph) or higher.
noteThe ABS warning light does not turn OFF in some cases unless the vehicle runs at 20 km/h (12 mph) or higher.
Is DTC No.C1242 set?
Replace the hydraulic unit (integrated with ASC-ECU) (Refer to ), and then go to Step 7.
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/How to Cope with Intermittent Malfunctions ).
 
STEP 7. Check whether the DTC is set again.
(1) Erase the DTC.
(2) Drive the vehicle at 20 km/h (12 mph) or higher.
noteThe ABS warning light does not turn OFF in some cases unless the vehicle runs at 20 km/h (12 mph) or higher.
Is DTC No.C1242 set?
Return to Step 1.
This diagnosis is complete.