Inspection Procedure 3: The Tight Corner Braking Phenomenon* Appears with the 4WD switch in the 4WD ECO or 4WD AUTO Position.


note
  • *Tight corner braking phenomenon: When a 4WD vehicle makes sharp cornering in a paved road at low speed (ex. parallel parking), there is a difference in turning radius between front and rear wheels. If such a difference can no longer be compensated by tyre slippage, the vehicle behaves as if it is under braking.
  • The vehicle is tuned so that the tight corner braking phenomenon appears at a certain level with the drive mode in the LOCK position.

COMMENTS ON TROUBLE SYMPTOM


If the tight corner braking phenomenon occurs only with the 4WD switch being on the 4WD ECO, 4WD AUTO position, the data received by 4WD-ECU from each ECU, the electronic control coupling, or 4WD-ECU may have a problem.

PROBABLE CAUSES



DIAGNOSIS PROCEDURE

STEP 1. Check for the tight corner braking phenomenon occurrence during driving on a flat road
Check if the tight corner braking phenomenon occurs during driving on a flat road with the 4WD switch being on the 4WD ECO or 4WD LOCK position.

Q. Does the tight corner braking phenomenon occur?
Go to Step 2.
This diagnosis is complete.

STEP 2. Wiring harness check
(1)Check the wiring harness between the 4WD-ECU connector (terminal SOL+, SOL-) and the electronic control coupling solenoid connector for damage or other problem.
(2)Check the connector(s) or terminal(s) or wiring harness above for damage or other problem.

Q. Is the check result normal?
Go to Step 3.
Repair the connector(s) or terminal(s) or wiring harness.

STEP 3. M.U.T.-III data list
Check the data list for the items below (Refer to ).

  • Item No.8: Steering angle sensor
  • Item No.11: Accelerator position
  • Item No.18: FL wheel speed sensor
  • Item No.19: FR wheel speed sensor
  • Item No.20: RL wheel speed sensor
  • Item No.21: RR wheel speed sensor
  • Item No.22: Yaw rate sensor
  • Item No.23: Lateral G sensor

Q. Is the check result normal?
Go to Step 5.
Perform the troubleshooting of the ABS system (Refer to GROUP 35B - Troubleshooting/Diagnosis Code Chart <Vehicles with ABS>), the ASC system (Refer to GROUP 35C - Troubleshooting/Diagnosis Code Chart <Vehicles with ASC>) or the engine control system (Refer to GROUP 13A - Troubleshooting/Inspection Chart for Diagnosis Code <4B1>, GROUP 13C -Troubleshooting/Inspection Chart for Diagnosis Code <4J1>, GROUP 13D -Troubleshooting/Inspection Chart for Diagnosis Code <4N1>). Then go to Step 4.

STEP 4. Check for the tight corner braking phenomenon occurrence during driving on a flat road
Check if the tight corner braking phenomenon occurs during driving on a flat road with the 4WD switch being on the 4WD ECO.

Q. Does the tight corner braking phenomenon occur?
YES (Coil current in the electronic control coupling solenoid is 0 A) : Measure the coil current when the tight corner braking occurs. If the coil current measures 0 A, replace the electronic control coupling (Refer to ). Then go to Step 5.
YES (Coil current in the electronic control coupling solenoid is other than 0 A) : Measure the coil current when the tight corner braking occurs. If the coil current is other than 0 A, go to Step 5.
This diagnosis is complete. Then go to Step 6.

STEP 5. Retest the system.

Q. Does the malfunction occur again?
Replace 4WD-ECU (Refer to ). Then go to Step 6 .
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/How to Cope with Intermittent Malfunctions ).

STEP 6. Retest the system.

Q. Does the malfunction occur again?
Replace the electronic control coupling (Refer to ). Then go to Step 7.
This diagnosis is complete.

STEP 7. Retest the system.

Q. Does the malfunction occur again?
Diagnose again from Step 1.
This diagnosis is complete.