If the battery is disconnected, several systems must be re-learned before they will work properly. This procedure applies to all ignition coils. First, disconnect the cable from the negative battery terminal. Next, remove the engine cover. For four-cylinder engines, remove the ignition coil harness fasteners. For five-cylinder engines, disconnect the electrical connector from the ignition coils by depressing the tabs to release the connectors. On four-cylinder engines, the ignition coil harness is rigid, so pull the coils up about an inch, disconnect all electrical connectors from the coils, and pull the harness and connectors away as a unit. Using special tool #T40039, slide the tool into the top slot of the coil and pull the coil up approximately 1-1/4 inches. If the special tool is not available, use two flat blade screwdrivers or a trim panel tool to carefully pry the ignition coil up, prying a little on each side to raise it. Grasp the ignition coil firmly and pull it straight up to remove each coil from the cylinder head. Before installing the coil, apply a little silicone dielectric compound to the inside of the spark plug boot, and installation is otherwise the reverse of removal.