Exam 9: Advanced Four Wheel Drive Systems Diagnosing 4wd and Awd Control Systems

Technician A says electronically controlled systems may use sensor inputs to control the center differential for front-rear torque bias. Technician B says the Porsche PTM system uses an electronically controlled motor in the transfer case. Who is correct?

List and briefly describe the most common 4WD operational modes.

Many AWD vehicles are based on _____ vehicles.

Technician A says all-wheel drive vehicles spread the tractive effort to all four driving wheels. Technician B says all-wheel drive vehicles operating under normal conditions are driving in 2WD. Who is correct?

Shifting between _____ can be done at a stop or while driving at any speed.

An open differential sends power to which axle?

A device which allows the front and rear axles to rotate at different speeds in full-time 4WD and AWD systems works to eliminate driveline windup.

During turns, the front wheels travel a shorter distance than the rear wheels.

The purpose of the interaxle differential is to compensate for differences in front-wheel and rear-wheel speeds such as when turning a corner.

What is the difference between 4WD and AWD systems?

Electronically controlled valves, hydraulic pumps, and wet clutches are components found in a(n) _____.

Most full-time AWD systems give the driver the option of 2WD or 4WD.

What does the acronym VTM-4 stand for?

Technician A says a transfer case may have a limited-slip, viscous-type clutch assembly. Technician B says a transfer case may have a multiple plate clutch assembly for limited slip. Who is correct?

Many late-model vehicles with 4WD systems have the ability to automatically switch from 2WD to 4WD.

Which statement concerning turning a corner with a 4WD system is correct?

Integrated full-time 4WD systems use _____ controls to enhance full-time operation.

A viscous coupling differential sends power to which axle?

Viscous coupling differentials send power to the axle or wheel that has the least traction.