On a downhill gradient, if an upshift occurs when the accelerator is released, there is no engine braking. To stop, the driver would need to apply greater force to the brakes.
And vehicle road speed tends to increase even if the accelerator is not touched.
Identifying a closed throttle and increasing road speed causes the system to respond initially by preventing further upshifts.
If brakes are then applied, a single downshift takes place. Downshift only occurs below a pre-set engine speed. This avoids application of peak engine braking torque.
The downhill identification gradient mode becomes inactive once the accelerator is depressed again.
