GM Service Manual Online
For 1990-2009 cars only

Caution: Exiting the vehicle, without first shifting into P (Park), may cause the vehicle to move, and you or others can be seriously injured. Because the vehicle has the Automatic Engine Start/Stop feature, the vehicle’s engine might seem to be shut off when you come to a complete stop. However, once the brake pedal is released, the vehicle can move. The vehicle’s engine can also restart at any time.

Shift to P (Park) and turn the ignition to LOCK/OFF, before exiting the vehicle.

Start the engine as you would any other engine. See "Starting Your Engine" in the owner manual for more information on starting. The hybrid system provides very quiet engine starting. If pulling a trailer with trailer brakes, see Towing a Trailer for more information.

Auto Stop

The vehicle has an Auto Stop feature. After a successful engine start, the Hybrid Powertrain Control Module (HPCM) may turn off the engine and operate in the Auto Stop mode. Some of the vehicle conditions that allow the engine to stop running and enter the Auto Stop mode are:

    • Ignition switch is in the ON/RUN position.
    • The hood is closed.
    • The gear selector is in P (Park), N (Neutral) or D (Drive).
    • The hybrid battery is at an acceptable state of charge.
    • The hybrid battery voltage, temperature or power limits are not exceeded. In very hot conditions, Auto Stop may be unavailable until the hybrid battery has cooled.
    • The engine is at operating temperature.

If you are on an incline, the hybrid drive motor can help keep your vehicle from rolling backwards, even if the engine is in Auto Stop.

With your foot off the brake and the vehicle on level ground, the hybrid drive motor may cause your vehicle to roll slowly forward, even when the engine is in Auto Stop.

To be sure your vehicle will not move or roll, always keep your foot firmly on the brake pedal until you are ready for the vehicle to move.

Engine OFF and AUTO STOP modes are indicated on the tachometer display. When the tachometer needle indicates OFF, the engine is not running and will remain off until the ignition key is placed in the START position or a remote vehicle start is performed. When the tachometer needle indicates AUTO STOP, the engine is not running but may Auto Start at any time without notice. See Tachometer for more information.

A chime will sound if the driver door is opened while in Auto Stop as a reminder that the ignition switch is not in the LOCK/OFF position. Always turn the ignition switch to LOCK/OFF and remove the key from the ignition switch when exiting the vehicle.

Auto Start

The vehicle also has an Auto Start feature. The engine will remain off while in Auto Stop mode until vehicle conditions require the engine to run. The near-instant starting of the engine from Auto Stop mode is called Auto Start. Some of the vehicle conditions that may cause the HPCM to Auto Start the engine are:

    • The hood is opened.
    • The gear selector is in M (Manual Mode) or R (Reverse).
    • The hybrid battery state of charge is too low.
    • The hybrid battery voltage, temperature or power limits are exceeded.
    • The engine is not at operating temperature.
    • Acceleration demands require the use of the engine.

EV Mode

The vehicle also has an EV mode which uses only the electric motor to move the vehicle. Depending on the state of battery charge, the vehicle can travel up to two miles (3.2 km) in EV mode. EV mode is unavailable when the vehicle is out of fuel.

While lightly accelerating, the vehicle will be propelled in EV mode.

If increased acceleration is required, or the vehicle achieves a speed of approximately 25 mph (40 km/h), the engine will start automatically. The engine will shut off at speeds below 25 MPH (40 km/h) unless the transmission is in M (Manual Mode) or Auto Stop is disabled.

During heavy acceleration, both the engine and hybrid electric motors supply power. A sensation similar to a transmission gear change can be felt as the transmission changes modes. Engine RPM may remain above 4,000 RPM for a longer period during hard acceleration.