The brief
This 520i was towed in because it wouldn't start at all. A no-start has a short list of likely causes, and a proper, holistic diagnosis is the way to find which one it is rather than throwing parts at it. On this car the fuel pump is run by an electronic control module, the EKPM, which manages how the pump delivers fuel to the engine. When that module fails, the pump doesn't get the right command, so the engine isn't getting fuel and won't fire, no matter how healthy the rest of the car is. While the car was in, the valve cover gasket got checked too and showed some leakage, the rubber hardened, so that got dealt with in the same visit. A failed module and a leaking gasket both stay broken until they're replaced.
The diagnosis
The holistic diagnosis confirmed the no-start was the EKPM, the electronic fuel pump control module, which had failed so the fuel pump wasn't being driven properly. The fuel pump itself was due replacement alongside the module, and the valve cover gasket was found leaking, the rubber hardened. That's an EKPM module and fuel pump replacement, reprogrammed to the car, plus a new valve cover gasket, rather than guessing at the no-start.
The work
The failed EKPM module was replaced with a new genuine BMW unit and the fuel pump renewed, both reprogrammed and coded to the car so the fuelling works properly. The valve cover came off, the hardened gasket replaced with a fresh genuine BMW-spec gasket and the cover torqued back down in sequence. The engine was cleaned up, the fuel system primed and checked for leaks, and the faults cleared. A road test confirmed the engine starting first time, running cleanly, the fuelling steady, the valve cover dry, and no warning lights.
The outcome
The 520i starting first time, running cleanly, the fuelling steady, the valve cover dry with no oil leak, and no warning lights, all turned around fast and with an after-repair guarantee. The car went home running properly again. A proper diagnosis found the failed module rather than us swapping a fuel pump and hoping, and doing the valve cover gasket in the same visit saved a return trip.