FEATURES - Engine Overspeed and Underspeed Protection pedal. Hill Start Aid can be disabled using the Hill Start Aid Disable switch (see Hill Start Aid Disable Switch ). Hill Start Aid activates by default on a road grade of 3% and whenever Neutral Idle Control Plus (NIC+) is active. (except in conditions requiring overspeed protection – see Engine Overspeed and Underspeed Protection on page 14). The transmission system will downshift at the earliest opportunity to enable higher than normal engine RPM to provide maximum engine braking.
NOTE 2 If Auto-park has been activated, the transmission will not exit Park ( P ) until the shifter is first moved to P before selecting another transmission mode. LOW Mode Engine Overspeed and Underspeed Protection LOW mode should be used any time you want to limit upshifting, hold lower gears, or improve engine braking through lower gear selection. For example, when driving down long grades or when coming to a stop. Selects lowest available gear for start gear. The starting gear cannot be changed in LOW mode. WARNING On slippery surfaces minimize engine braking in LOW mode. Excessive en- gine braking at higher engine RPM could cause a loss of traction and vehi- cle control.
The transmission system will upshift, if necessary, to prevent damage during an engine overspeed condition and will also downshift to prevent engine lug (driving in a high gear at low rpm) and a potential stall during an engine underspeed condition. Engine Overspeed Protection is active in Drive ( D ), Manual, and LOW modes; however, Engine Underspeed Protection is only active when in Drive ( D ) mode or Manual mode. NOTE NOTE This transmission initiates upshifts from Drive ( D ), Manual, and LOW modes for engine overspeed protec- tion. If the driver attempts to select a non- neutral mode without applying the service brake, the transmission will not shift into gear.
If this is attempted, the driver will need to re-select Neutral ( N ) and then press the service brake be- fore a new mode can be selected. Hill Start Aid (option) Hill Start Aid prevents unwanted vehicle movement on steep grades when transitioning from the brake to throttle If LOW is selected while moving, the transmission will not upshift 14 Y53-1331 (6/21)