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INSPECTION PROCEDURE 3: The Tight Corner Braking Phenomenon* Appears with the S-AWC Drive Mode-selector in the AUTO Position.
 
 
note
  • *Tight corner braking phenomenon: When a AWD 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 tire 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 SNOW or GRAVEL position.
 
 
COMMENTS ON TROUBLE SYMPTOM
If the tight corner braking phenomenon occurs only with the S-AWC drive mode-selector being on the AUTO position, the data received by AWC-ECU from each ECU, the electronic control coupling, or AWC-ECU may have a problem.
 
 
PROBABLE CAUSES
  • Malfunction of electronic control coupling
  • Malfunction of data transmitted from ASC system
  • Malfunction of data transmitted from the engine control system
  • Malfunction of wheel speed sensor
  • Malfunction of steering wheel sensor
  • Malfunction of AWC-ECU
  • Malfunction of S-AWC drive mode-selector
 
 
DIAGNOSIS
Required Special Tools:
  • MB992006: Extra fine probe
STEP 1. Check for the tight corner braking phenomenon occurrence during driving on a flat road
(1) Operate the drive-mode selector to switch the drive mode to AUTO.
(2) Turn the steering wheel on a flat road clockwise or counterclockwise 360°or more.
(3) Move the selector lever to D range (1st gear) to start the vehicle slowly.
(4) The vehicle should hesitate to move forwards and a tight corner braking phenomenon should occur.
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 AWC-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.
Is the check result normal?
Go to Step 3.
Repair the connector(s) or terminal(s) or wiring harness.
 
STEP 3. Scan tool (M.U.T.-IIISE) data list
Check the data list for the items below.
  • Item No.21: Steering angle
  • Item No.24: Accelerator position
  • Item No.35: Wheel speed (FL)
  • Item No.36: Wheel speed (FR)
  • Item No.37: Wheel speed (RL)
  • Item No.38: Wheel speed (RR)
  • Item No.39: Yaw rate
  • Item No.40: Lateral G
Is the check result normal?
Go to Step 4.
Perform the troubleshooting of the ASC system (Refer to GROUP 35C - Diagnosis, Diagnostic Trouble Code Chart ) or the engine control system (Refer to GROUP 13A - Diagnosis, Diagnostic Trouble Code Chart ). Then go to Step 4.
 
STEP 4. Check for the tight corner braking phenomenon occurrence during driving on a flat road
(1) Execute "Test" (item No. 1 Control OFF) on scan tool (M.U.T.-IIISE) special function.
(2) Operate the drive-mode selector to switch the drive mode to AUTO.
(3) Turn the steering wheel on a flat road clockwise or counterclockwise 360° or more.
(4) Move the selector lever to D range (1st gear) to start the vehicle slowly.
(5) The vehicle should hesitate to move forwards and a tight corner braking phenomenon should occur.
Does the tight corner braking phenomenon occur?
: Measure the coil current when the tight corner braking occurs. If the coil current measures 0 A, replace the transfer assembly (Refer to ) or electronic control coupling (Refer to ). Then go to Step 5.
: 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 5.
 
STEP 5. Retest the system.
Does the malfunction occur again?
Replace the AWC-ECU (Refer to ).
This diagnosis is complete.