If the battery is disconnected, several systems must be re-learned before they will work properly. For all engines, start by disconnecting the cable from the negative battery terminal and removing the engine cover or air filter housing. For 1.4L, 1.8L, and 2.0L turbocharged engines, remove the air filter housing lid or any air intake duct work to access the coils, then remove the nuts and ground cables from the coil mounting fasteners. Disconnect the coil electrical connectors and remove the coil fasteners, using a prybar or similar tool to carefully pry the ignition coil from the valve cover and spark plug. Apply a little silicone dielectric compound to the inside of the spark plug boot before installing the coil, with installation being the reverse of removal. For the 2.0L non-turbocharged engine, mark the location of the spark plug wires and disconnect them from the coil terminals, then disconnect the electrical connector from the coil, remove the bolts securing the coil, and apply silicone dielectric compound to the inside of the spark plug wire boot before installation. For all other engines, on four-cylinder engines, remove the ignition coil harness fasteners, and on five-cylinder engines, disconnect the electrical connector from the ignition coils by depressing the tabs. For four-cylinder engines, 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 it up approximately 1-1/4 inches; if the tool is not available, use two flat blade screwdrivers or a trim panel tool to carefully pry the ignition coil up. Grasp the ignition coil firmly and pull it straight up, then apply a little silicone dielectric compound to the inside of the spark plug boot before installing the coil, with installation being the reverse of removal.