The main computer in all models sits in front right behind the glovebox, in the passenger compartment. To access the ECM, remove the glovebox. When the engine is on, hitting the computer hard on the side will show if it's working right; when the computer is damaged, the engine may struggle and cut off while the diagnostic tool reveals broken engine data. If the computer doesn't pass the test, check its electrical connections because matching colored parts connect to special spots in the computer. When nothing seems wrong, let a professional at a dealership or other authorized repair place check your unit. The ECM for T100 vehicles is found right behind the side trim panel where it was originally installed. Turn off the vehicle, then unplug the battery cable from its negative terminal. Next, disconnect the ECM's electrical plug-ins while making sure you remain connected to a vehicle ground or touch a good car ground before dealing with the ECM. To undo the ECM mounting bolts, carefully pull out the unit by unscrewing them. Reinstall it by repeating these steps in reverse order.