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DTC C1392: Incomplete learn (Longitudinal G)
DTC C1393: Incomplete learn neutral(Lateral G)
 
 
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 - CAN Bus Diagnostics Table ).
  • Whenever ECU is replaced, ensure that the CAN bus lines are normal.
 
 
OPERATION
When the scan tool MB991958 is operated, the ASC-ECU will learn the neutral position of the G sensor and then store it in its memory.
 
 
 
DTC SET CONDITIONS
The ASC-ECU will set this DTC when it has not learned the neutral position of the G sensor.
 
 
 
PROBABLE CAUSES
  • The neutral position of the G sensor has not been learned.
  • ASC-ECU malfunction
 
 
 
 
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.C1392 or C1393 set?
Go to Step 3.
This diagnosis is complete.
 
STEP 3. Check the G sensor-related DTC.
Use the scan tool MB991958 to check whether the G 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 "Lateral G sensor calibration" and "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 "Lateral G sensor calibration" and "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 (Refer to ).
  • Item 08: Lateral G sensor
  • Item 09: G Sensor
  • Item 17: G sensor offset
  • Item 20: Lateral G sensor offset
Is the check result normal?
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.
Is DTC No.C1392 or C1393 set?
Replace the hydraulic unit (integrated with ASC-ECU) (Refer to ), and then go to Step 7.
This diagnosis is complete.
 
STEP 7. Check whether the DTC is set again.
Is DTC No.C1392 or C1393 set?
Return to Step 1.
This diagnosis is complete.