Sorento no start. Crank sensor ????

Hey all. I need some help. I have a 2003 Sorento that won't start. It has no power on the fuses that the main relay powers up. The Ecu is not grounding the relay. Does anyone know what triggers the Ecu to ground the relay? I can ground the relay and it will run fine but sets a code p0700. Thanks for any help possible.

Hey all. I need some help. I have a 2003 Sorento that won't start. It has no power on the fuses that the main relay powers up. The Ecu is not grounding the relay. Does anyone know what triggers the Ecu to ground the relay? I can ground the relay and it will run fine but sets a code p0700. Thanks for any help possible.
The ignition switch powers the Ecu which supplies the ground. This switch plugs in the back of the key cylinder. Check for corroded wire.