Hope this is useful for anyone out there as it was for me:

2012 E70 xdrive35D (diesel) here with 92K miles - started having issues not starting up like if it was out of fuel. Then showing several warnings on the screen:
DSC, Fuel pump and transmission errors. After reading this post I tried finding the fuel pump relay as suggested above - nope, mine doesn't have it. So I did a search for the EKP module - found it! Trunk, open the spare tire compartment then remove the back plastic storage bin that goes across the trunk. The EKP is located to the right side, pretty accessible. But get this: my BMW dealer wouldn't sell it to me as it must be programmed by the dealer. So ended up bringing the car in. $890 later ($448 in parts and $563 in labor minus some discount) I'm back in business but pretty disappointed as to what to expect with these new modern BMWs.