So my wifes car won't start the anti theft light keeps flashing need some help. I have the master key and still won't start when I unlock the doors with the key fob but the hazards flashes twice and the anti theft is continuous blinking I'm so lost and over it

 

Yesterday I change some parts on my m5 143hp diesel clutch doble flywheel and other parts remove the injectores one by one clean put new gaskets every thing new and in the end it doesn start it cranks but no star better it stars but doesn t stay on it stops. I think it’s the crank sensor on the gear box that is damage in you case the car should start and after 3 seconds the light should be off