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DTC C123C: Sensor cluster malfunction
 
 
caution
  • Whenever the steering wheel sensor is replaced, always calibrate the sensor (Refer to GROUP 35C - Steering Wheel Calibration ). Then make the steering wheel sensor learn the compensation which the PHEV-ECU has stored (Item: Initialization, Item No. 3: Steering Angle offset reset ).
  • When the hydraulic unit (integrated with ASC-ECU) is replaced, after vehicle information from ETACS-ECU is registered (power supply mode of the electric motor switch: OFF from ON), always carry out the calibration of all sensors (steering wheel sensor, G and yaw rate sensor, and brake fluid pressure sensor) at one time. (Refer to GROUP 35C - All Sensor Calibration ).
  • Whenever ECU is replaced, ensure that the CAN bus lines are normal.
 
 
DTC SET CONDITIONS
The PHEV-ECU sets DTC C123C when the lateral acceleration/yaw rate sensor fails.
 
 
 
PROBABLE CAUSES
  • Malfunction of the G and yaw rate sensor.
  • Malfunction of wheel the speed sensor.
  • Improper installation of steering wheel sensor.
  • Malfunction of the steering wheel sensor.
  • Improper installation of hydraulic unit.
  • Malfunction of the PHEV-ECU.
 
 

 
 
DIAGNOSIS
STEP 1. Using scan tool (M.U.T.-IIISE), check whether the other DTC is set.
Check whether the DTC is set in the ASC-ECU (Refer to GROUP 35C - Diagnostic Trouble Code Chart ).
Is the DTC set?
Troubleshoot for the relevant DTC.
Go to Step 2.
 
STEP 2. Using scan tool (M.U.T.-IIISE), check whether the other DTC is set.
Check whether the wheel speed sensor-related or steering wheel sensor-related DTC is set or not (Refer to ).
Is the DTC set?
Troubleshoot for the relevant DTC.
Go to Step 3.
 
STEP 3. 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 35C - Hydraulic Unit (integrated with G and yaw rate sensor) ].
Is the check result normal?
Go to Step 4.
Install the hydraulic unit properly, and execute "G and yaw rate sensor calibration". (Refer to GROUP 35C - G and yaw rate sensor calibration ). Then go to Step 6.
 
STEP 4. Using scan tool (M.U.T.-IIISE), check the data list. <PHEV-ECU>
Check that the following data list display contents are normal (Refer to ).
  • Item No.330: Yaw rate
  • Item No.331: Lateral acceleration
Is the check result normal?
Go to Step 5.
Replace the hydraulic unit [Refer to GROUP 35C - Hydraulic Unit (integrated with G and yaw rate sensor) ], and execute "G and yaw rate sensor calibration". (Refer to GROUP 35C - G and yaw rate sensor calibration ).
 
STEP 5. Steering wheel sensor installation check.
Check that the steering wheel sensor is installed correctly (Refer to GROUP 35C - Steering Wheel Sensor ).
Is the check result normal?
Go to Step 6.
Reinstall the steering wheel sensor correctly, and then go to Step 6.
 
STEP 6. Wheel alignment check.
Refer to GROUP 33 - On-vehicle Service, Front Wheel Alignment Check and Adjustment .
Is the check result normal?
After checking the wheel alignment, carry out calibration of steering wheel sensor to make ASC-ECU relearn the neutral point (Refer to GROUP 35C - Steering Wheel Calibration ) and make the steering wheel sensor learn the compensation which the PHEV-ECU has stored (Item: Initialization, Item No. 3: Steering Angle offset reset ). Then go to Step 7.
After adjusting the wheel alignment, carry out calibration of steering wheel sensor to make ASC-ECU relearn the neutral point (Refer to GROUP 35C - Steering Wheel Calibration ) and make the steering wheel sensor learn the compensation which the PHEV-ECU has stored. (Item: Initialization, Item No. 3: Steering Angle offset reset ). Then go to Step 7.
 
STEP 7. Using scan tool (M.U.T.-IIISE), check the data list. <PHEV-ECU>
Refer to .
  • Item No.333: Steering angle
Is the check result normal?
Go to Step 8.
Replace the steering wheel sensor (Refer to GROUP 35C - Steering Wheel Sensor ).
 
STEP 8. Using scan tool (M.U.T.-IIISE), check whether the DTC is set again.
Recheck the DTC.
(1) Erase the DTC.
(2) Turn off the power supply mode of the electric motor switch.
(3) Turn on the power supply mode of the electric motor switch.
(4) Check the DTC.
Is the DTC set?
Replace the PHEV-ECU (Refer to ).
The trouble can be an intermittent malfunction (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).