Do you know how to do automotive electrical testing , with a volt meter . Check out videos on youtube basic automotive electrical testing . Do you have a scan tool ? That would be a good first step . Do you have any idea how many elctronic control modules are on your vehicle ? Do you know what a serial data communication network is . C.A.N How to Diagnose Controller Area Network CAN
When you turn the key to start do you know what happens ?
Circuit Description (Key Start)
For ignition switch power modes refer to Body Control System Description and Operation . When the ignition switch is placed in the Start position a discrete signal is supplied to the body control module (BCM) notifying it that the ignition is in the Start position. The BCM then sends a message to the powertrain control module (PCM)/engine control module (ECM) notifying it that CRANK has been requested. At the same time the BCM is supplying 12 volts for the IGN 1 relay closing it and supplying battery positive voltage for the crank relay coil. The PCM/ECM verifies that the transmission is in Park or Neutral. If it is, the PCM/ECM grounds the control circuit of the crank relay. When this occurs battery positive voltage is supplied through the switch side of the crank relay to the S terminal of the starter solenoid.
What you need to do is have it towed to the dealer !