On my "E" 350 had the same problem. Mine was caused by easing the hood down and not giving a good hard shove at the last moment to get the lock to fully seat. The cable or the latch in the grill wouldn't release. I had to take off the windshield wipers, that plastic panel under the wipers to get access to remove the hinge bolts completely removing the hood. Reset the hood latch and put everything back together. Just don't baby the hood when closing. If you have to go this route, operate your cable release before reassembly to make sure cable has not parted somewhere along its path.