GM Service Manual Online
For 1990-2009 cars only

This vehicle is equipped with a battery run down protection feature. If a car exhibits a low or dead battery after an overnight set, or goes down over a period of 2 or 3 days, the electrical system should be checked for an excessive electrical drain. The process of a car exhibiting a low or dead battery after an overnight set, or going down over a period of 2 or 3 days, is called a parasitic Current Draw.

Battery Rundown Protection Feature

A battery rundown protection feature has been added to this vehicle in order to extend the battery life. INADVERTENT and PARASITIC loads (modules or functions that drain current from the battery) are automatically turned off after predetermined time intervals:

    • Parasitic loads: Loads that draw small amounts of current when the ignition is Off, such as the radio and the remote keyless entry system.
    • Inadvertent loads: Higher current loads that can be left on, such as the courtesy lights, glove compartment light, and luggage compartment light.

Battery rundown protection operates in two different modes:

    • Dealer/plant mode: Battery rundown protection is in the dealer/plant mode when the vehicle has logged less than 15 miles since power up. For inadvertent loads, (the light left on accidently, the door left ajar), battery power turns off after three minutes. Opening and closing a door, or cycling the ignition restores inadvertent power functions. Also, if the vehicle is left untouched for three days, battery power shuts off, disabling parasitic load drains to the battery. At this point all radio presets will be erased and the remote keyless entry function resets by cycling the ignition.
    • Customer mode: Battery rundown protection is in the customer mode when the vehicle has logged greater than 15 miles since power up. Customer mode operates in the same manner as described above, except that inadvertent power shuts off after 20 minutes and parasitic power shuts off after 24 hours.

Battery Protection During Vehicle Storage

Today's vehicles have high technology electronic devices which result in small but continuous current drains on the battery. The current drains are commonly called Parasitic Loads. Vehicles that are not used for an extended period of time may develop discharged and permanently damaged batteries resulting from parasitic loads. (A discharged battery can freeze at temperatures as high as -7°C (20°F). Freezing permanently damages a battery). In order to help prevent this condition for long term storage of 20 days or longer, disconnect the battery cable.

Notice: Turn OFF the ignition when connecting or disconnecting the battery cables, the battery charger or the jumper cables. Failure to do so may damage the PCM or other electronic components.

If this is not possible, recharge the batteries periodically (every 20-45 days) until the green dot is visible. Refer to Battery Charging . Once the vehicle is returned to service, reset the radio push-button tuning and the clock.

Battery Ratings

A battery has two ratings: Reserve Capacity and Cold Cranking Amperage.

Reserve Capacity

The Reserve Capacity is an estimate of how long the vehicle can be driven with no generator output, the headlamps turned on, and minimum electrical load (with most accessories turned off). Reserve Capacity is the maximum amount of time (in minutes) for a fully charged battery, being discharged at a temperature of 27°C (80°F), to reach a terminal voltage of 10.5 Volts. (Other temperatures or current draws, the state of charge, or the condition of the battery will all affect how long the battery will actually last when one drives the vehicle and there is no generator output to the battery).

Cold Cranking Amperage

The Cold Cranking Amperage is an indication of the ability of the battery to crank the engine at cold temperatures. The capacity rating is the minimum amperage the battery must maintain for 30 seconds at -18°C (0°F), while maintaining at least 7.2 volts. (The actual performance of a battery varies with actual temperature.)