For release: Sept. 27, 2007
CHEVROLET TAHOE AND GMC YUKON HYBRID: LIVING WITH A FULL-SIZE HYBRID
Owning a new Chevrolet Tahoe or GMC Yukon Hybrid is easier than one might imagine. Outwardly, much about these vehicles seems unchanged from the gasoline-only models, with the exception of some exterior details, subtle interior styling and several functional modifications. While the applied technology is certainly advanced, operationally these are easy vehicles to drive and enjoy. In fact, there is no difference in passenger seating capacity, and towing and payload are highly competitive with other non-hybrid SUVs in the segment.
The following are some tips on owning and operating the Tahoe and Yukon Hybrid sport utility vehicles.
Starting the vehicle
To start the all-new Tahoe and Yukon Hybrid, just turn the ignition key to Start as you would any other vehicle. The gasoline engine will initially start and run, but may shut off soon after it has warmed up. This is normal, as the hybrid system is always trying to conserve fuel. Once started, the vehicle may be driven in electric-only mode up to 30 mph. Under high-load conditions, the gasoline engine may restart to provide additional pulling power.
The available remote start feature functions the same as on standard gasoline-only models. For safety, the system will only allow two consecutive remote start cycles via the key fob before the vehicle must be started using the ignition key.
Driving for best economy
By using the analog economy gauge found in the instrument cluster of all Tahoe and Yukon Hybrid models, drivers can maintain the most efficient driving style by keeping the gauge at its optimum economy indication as often as possible. Also, any time the gasoline engine is shut down — indicated when the tachometer needle points to the Auto Stop position, just below the zero mark — the driver will know when the vehicle is being powered only by electricity, which is the most efficient propulsion method.
Transmission operation
Because the Tahoe and Yukon Hybrid are powered through an electrically variable transmission, shifting is nearly imperceptible. Even during fixed ratio shifts, the smooth, computer-controlled clutch engagements and disengagements are barely noticeable by vehicle occupants. The overall effect is one of smooth, even power flow as the vehicle is accelerated from a stop up to cruising speed.
Operating in reverse
Driving in reverse is no different than any other vehicle, except that the Tahoe and Yukon Hybrid models use only electric power when backing up. Although the vehicle is powered electrically when in reverse, the gasoline engine may operate depending on conditions.
Hybrid battery maintenance
The ESS battery pack is warranted for eight years/100,000 miles and requires no owner maintenance.
Electric A/C compressor
The 300-volt air conditioning compressor is designed to provide continuous cooling regardless of whether the gasoline engine is running or not. For the best results, set the climate control to Auto mode. For the most efficient operation (gasoline engine in Auto Stop mode), set the temperature as high as possible or turn off the climate control completely. Continuous use of the air conditioning will cause the engine to start more frequently in the Auto Stop mode.
Because of the quiet operation of hybrid vehicles, the air conditioning compressor may occasionally be heard, especially when the gasoline engine is shut off.
Regenerative braking
The regenerative braking system works in concert with the hydraulic braking system. The system uses a brake pedal emulator, which provides progressive resistance as the pedal is depressed. This consistent pedal feel is very much like that of a standard hydraulic braking system in operation.
Because there are two braking systems — regenerative and hydraulic — more braking power is available than that found on gasoline-only models. Because of this, braking distances will be noticeably shorter.
From time to time you may hear the computer-controlled pump re-pressurizing the hydraulic brake accumulator. This is normal and necessary to the safe operation of the vehicle. Note that actuating the brake pedal repeatedly will deplete the accumulator pressure more quickly and cause the pump to cycle more often.
Gasoline engine operation
Typically, the hybrid control system will shut off the gasoline engine when it is not needed for propulsion. However, there may be instances when the engine will remain running after it is started:
- The engine or transmission is not fully warmed up
- The transmission or ESS temperature is high
- The ESS charge level is low and requires recharging
- The hood is not fully closed
- The “Service Engine Soon” light is illuminated
Situations in which the engine will restart include:
- The accelerator pedal is depressed in demand for heavy acceleration
- The engine must run to meet the current climate control settings
- The ESS charge level is low and requires recharging
Typical hybrid sounds
Hybrid vehicles utilize numerous electric motors throughout the body and in the transmission. At different times during vehicle operation these motors may start and stop as part of normal vehicle operation. You may even hear a slight whirring sound coming from these motors, especially when the gasoline engine is in Auto Stop mode. These sounds are normal for a hybrid vehicle.
Electric Power Steering (EPS)
The use of an electrically driven 42-volt variable-assist power steering rack results in virtually no vibration typically caused by a mechanical belt and pulley drive. The electric power steering system also provides variable effort for better driver feedback, improved on-center feel and reduced steering effort during slow-speed maneuvers in parking lots, etc. The system also provides up to a 0.5-mpg fuel economy improvement by reducing parasitic losses common in belt-driven hydraulic pumps
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