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Inspection Procedure 12: ABS/stability control/TCL operates too frequently.
 
 
caution
  • If there is any problem in the CAN bus lines, an incorrect DTC may be set. Prior to this diagnosis, always 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.
  • When the column switch assembly (integrated with steering wheel sensor) is replaced, always carry out calibration to make ASC-ECU learn the neutral point (Refer to ).
 
 
COMMENTS ON TROUBLE SYMPTOM
  • Although the cause of the trouble cannot be clearly resolved since it depends on the running status and road surface condition, the malfunction of the hydraulic circuit may occur if any DTC is not detected.
  • If wheels and tires other than the ones with genuine specified size are mounted, the ABS/stability control/TCL may be activated prematurely.
  • If a non-genuine braking device or non-genuine impact reduction device is mounted, the ABS/stability control/TCL may be activated prematurely.
 
 
 
PROBABLE CAUSES
  • Mounting of wheels and tires other than with genuine specified size
  • Tire pressure abnormality
  • Tire wear and deterioration
  • Mounting of non-genuine braking device or impact reduction device
  • Wheel alignment abnormality
  • Malfunction of brake related parts
  • Malfunction of the wheel speed sensor
  • Column switch assembly (integrated with steering wheel sensor) malfunction
  • Malfunction of hydraulic unit (integrated with ASC-ECU)
  • Malfunction of hydraulic circuit
  • External radio wave noise interference
 
 
 
 
DIAGNOSIS
STEP 1. Check the wheels and the tires.
Carry out the following check.
  • Size check of wheels and tires
  • Tire wear and deterioration statuses
  • Check the tire pressure.
    noteFor the tire pressure, refer to the tire pressure label attached to the lower section of driver's side door striker.
Is the check result normal?
Go to Step 2.
Correct the wheels and tires in good condition.
 
STEP 2. Using scan tool (M.U.T.-IIISE) DTC.
Using scan tool (M.U.T.-IIISE), check that DTC is set in the ASC system (Refer to ).
Is the DTC set?
Perform troubleshooting on ASC-ECU.
Go to Step 3.
 
STEP 3. Check of brake system related components other than hydraulic unit (integrated with ASC-ECU)
At the same time with the following checks, also check that no parts other than the genuine parts are mounted.
  • Brake pad check (Refer to GROUP 35A - On-vehicle Service, Brake Pad Check ).
  • Brake disc runout check (Refer to GROUP 35A - On-vehicle Service, Brake Disk Check ).
  • Brake drag force check (Refer to GROUP 35A - On-vehicle Service, Brake Drag Force Check ).
Is the check result normal?
Go to Step 4.
Repair or replace the part(s) having damage or other problems.
 
STEP 4. Wheel alignment check
At the same time with the following checks, also check that no parts other than the genuine parts are mounted.
  • Front wheel alignment check (Refer to GROUP 33 - On-vehicle Service, Front Wheel Alignment Check and Adjustment ).
  • Rear wheel alignment check (Refer to GROUP 34 - On-vehicle Service, Rear Wheel Alignment Check and Adjustment ).
Is the check result normal?
Go to Step 5.
Repair or replace the part(s) having damage or other problems.
 
STEP 5. Wheel speed sensor check
Check that no non-genuine electronic device or no wiring harness of other than genuine electronic device is mounted near the wheel speed sensor (at wheel speed detection section and wiring harness section) (Refer to <Front> or <Rear>.)
Is the check result normal?
Go to Step 6.
Remove the non-genuine electronic device or the wiring harness of non-genuine electronic device.
 
STEP 6. Using scan tool (M.U.T.-IIISE) data list
Check the following data list (Refer to ).
  • Item No.01: FL wheel speed sensor
  • Item No.02: FR wheel speed sensor
  • Item No.03: RL wheel speed sensor
  • Item No.04: RR wheel speed sensor
  • Item No.05: Steering angle sensor
  • Item No.06: Yaw rate sensor
  • Item No.08: Lateral G sensor
Is the check result normal?
Go to Step 7.
: Check the installation status of corresponding wheel speed sensor (Refer to <Front> or <Rear>).
: Check the installation status of hydraulic unit (integrated with ASC-ECU) (Refer to ).
: Check the installation status of column switch assembly (integrated with steering wheel sensor) (Refer to GROUP 54A - Column Switch ).
 
STEP 7. ABS/stability control/TCL operation check
Is the check result normal?
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/How to Cope with Intermittent Malfunctions ).
Replace the hydraulic unit (integrated with ASC-ECU) (Refer to ).