Inspection Procedure 3: The Tight Corner Braking Phenomenon* Appears with the Drive Mode Selector in the 2WD or 4WD 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 selector in the LOCK position.

COMMENTS ON TROUBLE SYMPTOM


If the tight corner braking phenomenon occurs with the drive mode selector being on the 2WD position, the electronic control coupling may have a problem. If the tight corner braking phenomenon occurs only with the drive mode selector being on the 4WD 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 drive mode selector being on the 2WD or 4WD position.

Q. Does the tight corner braking phenomenon occur?
Go to Step 2.
Go to Step 5.

STEP 2. Wiring harness check
Check the wiring harness between the C-130 4WD-ECU connector (terminal No. 1) and the D-113 electronic control coupling solenoid connector (terminal No. 1) for damage or other problem.

Q. Is the wiring harness in good condition?
Go to Step 3.
Repair damage or other problem in the wiring harness. Then go to Step 7.

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

  • Item 16: FL wheel speed sensor
  • Item 17: FR wheel speed sensor
  • Item 18: RL wheel speed sensor
  • Item 19: RR wheel speed sensor
  • Item 26: Throttle position

Q. Does the service data meet the standard value range?
Go to Step 5.
Perform the troubleshooting of the ABS system (refer to GROUP 35C - Troubleshooting ) or the troubleshooting of the engine control system (refer to GROUP 13A - Troubleshooting ). 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 drive mode selector being on the 2WD position.

Q. Does the tight corner braking phenomenon occur?
YES (Coil current 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 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.
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 Cope with Intermittent Malfunction .)

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. Check whether the diagnosis code is reset.

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