To replace a car battery, a mechanic will first install a temporary power source to preserve the computer memory of your navigation, audio, engine management, and other electronic systems. With the electronics safeguarded, the technician will disconnect the negative terminal from the battery, followed by the positive cable. The battery tie down device is loosened, and the old battery is removed and discarded according to state and local regulations. The cable ends and wires are carefully inspected for signs of corrosion or other damage before the new battery is installed, strapped down, connected, and dressed with an anti-corrosion compound.
At this point, some vehicles may require programming of the Powertrain Control Module (PCM). Finally, your vehicle is started and the output of the charging system is tested.