System Description

AWD SYSTEM


System Description


DESCRIPTION
- Electronic control allows optimal distribution of torque to front/rear wheels to match road conditions.
- Makes possible stable driving, with no wheel spin, on snowy roads or other slippery surfaces.
- On roads which do not require AWD, it contributes to improved fuel economy by driving in conditions close to rear-wheel drive.
- Sensor inputs determine the vehicle's turning condition, and in response tight cornering/braking are controlled by distributing optimum torque to front wheels.

NOTE:
- When driving, if there is a large difference between front and rear wheel speed which continues for a long time, fluid temperature of drive system parts becomes too high and AWD warning lamp flashes rapidly.
(When AWD warning lamp flashes, vehicle changes to rear-wheel drive conditions.) Also, optional distribution of torque sometimes becomes rigid before lamp flashes rapidly, but it is not malfunction.
- If AWD warning lamp is flashing rapidly, stop vehicle and allow it to idle for some time. Flashing will stop and
AWD system will be restored.
- When driving, AWD warning lamp may flash slowly if there is a significant difference in diameter of the tires.
At this time, vehicle performance is not fully available and cautious driving is required. (Continues until engine is turned OFF.)
- If the warning lamp flashes slowly during driving but remains OFF after engine is restarted, the system is normal. If it again flashes slowly after driving for some time, vehicle must be inspected.
- When the difference of revolution speed between the front and rear wheel the shift occasionally changes to direct 4-wheel driving conditions automatically. This is not malfunction.

ELECTRIC CONTROLLED COUPLING

Operation Principle





1. AWD control unit supplies command current to electric controlled coupling (AWD solenoid).
2. Control clutch is engaged by electromagnet and torque is detected in control clutch.
3. The cam operates in response to control clutch torque and applies pressure to main clutch.
4. Main clutch transmits torque to front wheels according to pressing power.





- Transmission torque to front wheels is determined according to command current.

AWD CONTROL UNIT
- Controls distribution of drive power between rear-wheel drive





(0:100) and AWD (50:50) conditions according to signals from sensors.
- Self-diagnosis can be done with CONSULT-III.

AWD WARNING LAMP
Turns ON when there is a malfunction in AWD system. It indicates that fail-safe mode is engaged and vehicle change to rear-wheel drive or shifting driving force-AWD (Front-wheels still have some driving torque).
Also turns ON when ignition switch is turned ON, for purpose of lamp check. Turns OFF approximately for 1 seconds after the engine starts if system is normal.

AWD Warning Lamp Indication