Grade Control

While the vehicle is driving up a hill, the gear is fixed to the 3rd to avoid repeated gear shift between the 3rd and 4th gears.

When the vehicle is descending a steep slope at a speed of approximately 80 km/h (50 MPH), a 4th to 3rd downshift occurs automatically when the brake pedal is depressed. This gearshift control is cancelled when the accelerator pedal is depressed.

The TCM performs these controls based mainly on the throttle opening, engine speed and vehicle speed.

Fig 1: Gear Shifting Position - Driving In Up & Down Grade Areas

Courtesy of SUBARU OF AMERICA, INC.

Fig 2: Grade Control Pattern Range Graph

Courtesy of SUBARU OF AMERICA, INC.