The thermostat may fail to close completely, causing the Check Engine Light to illuminate. This problem will prevent the engine from reaching normal operating temperature; a new thermostat should be installed.
A weak or dead battery may be caused by a defective radio (MYGIG radios only). To check, turn off the car and remove the key from the ignition. Wait thirty to forty seconds and then check if the radio back light is flickering. If the back light flickers every twenty seconds, the radio should be replaced.
If the engine does not crank (or cranks but won't start), the wireless control module (WCM) may have locked up. This is due to static discharge through the ignition key. A revised model should be installed, but simply disconnecting the negative terminal of the battery for thirty seconds will temporarily reset the module so you can start the car.