the 'L' indicates a faulty setting for hydraulic or seat switch

check the seat switch and circuit first before diving into the other checks for the E72

now as for the E72 it does not designiate any particular contactor coil, the system just sees that one of them is not passing the post test and shuts the system down.
in possible causes it lists them as:
-faulty line contactor
-faulty steering contactor
-faulty pump contactor
-faulty main harness
-faulty logic unit

so you have your work cut out for you to find the problem.

since you are getting the 'L' code first my guess is the seat switch circuit is failing and the system may be seeing a contactor issue right after it throws the code for the L so it follows it up with the 72 code because the contactor is not pulling in when it expects to see it.
one other thing you may want to check is the logic card connector plugs, make sure they are plugged in and also pull them and check the pins for corrosion.