4WD Control System Operation Description
Precautions: Precautions for Diagnosing Trouble · Precautions for Driveline / Axle · General safety (00)
The 4WD control system performs the feedback control and the feedforward control to optimize the distribution of the driving force for the rear wheels. The feedback control which controls it by sensing front wheel(s) slip information, revolution difference between front and rear wheels. The feedforward control which controls it according to information of accelerator opening, steering turning angle and vehicle speed.
Driving Mode Control
AUTO mode
2WD is set in this mode basically, however driving force is distributed to rear wheels when front wheel slip is detected.
SPORT mode
4WD is set in this mode basically. This mode improves accelerator-torque characteristics at narrow and middle throttle opening.
SNOW mode
4WD is set in this mode basically and ensures higher stability against slippery road surface improving traction at low ยต road.
LOCK mode
Selecting to this LOCK mode is allowed only in SNOW mode. However, vehicle speed becomes 60 km/h (37 mile/h) or higher, this LOCK mode is selected to SNOW mode automatically.
4WD System Protective Control
Protective control against driving on different diameter tire
Revolution difference between rear wheels and front wheels exceeds the limit when driving on different diameter tire(s) other than standard tire, electric current to rear drive coupling unit is stopped. And, blinking 4WD warning light and information display warns the driver of this situation.
Protective control against overload driving
When any of 4WD line overheats due to overload driving, electric current to rear drive coupling unit is stopped. And, blinking 4WD warning light and information display warns the driver of this situation.
ABS Control for ABS Operation
To satisfy ABS function, electric current to rear drive coupling unit is stopped when ABS is in operation.
Vehicle Dynamics Synthetic Control
BCM executes 4WD control module and P/S control module and vehicle dynamics synthetic control. For more detail of vehicle dynamics synthetic control, refer to Description of Vehicle Dynamics Synthetic Control.