No start problem
After two weeks at the BMW dealer, my intermittent no start problem was fixed. Turned out to be the BUS line between the DDE and CAS module. It all started with the vehicle not starting within 30 seconds of turning off after a 45 minute drive (crank only). The car on the service hoist pic and fuel error message displayed on the Nav screen. It started a short time later and happened again about a week later 90 seconds after turning the vehicle off. The dealer installed a fuel pressure gauge to the low side and drove the car for a few days trying to duplicate the no start, which was successful. There was no pressure at the low side and the fuel pump was not being activated. BMWNA instructed the dealer to replace the CAS module but that didn't resolve the problem. BMWNA instructed the dealer to drain the fuel tank and remove the low pressure pump for a corrosion inspection. Since there was no presence of corrosion, BMWNA instructed the dealer to sample the fuel for contamination (none present). Removal of the high pressure rail sensor was next ( no corrosion). BMWNA was insistent the problem was fuel related. Fortunately, the technician finally convinced them otherwise. Turns out there was no BUS line in Pin 36 of the DDE connector via schematic (uncertain if missing). Dash removal was required to inspect the body harness splice point, which revealed an open circuit. Technician ran a new dedicated BUS line between the DDE and CAS module, which resolved the problem. Kudos to Joe, the BMW technician for resolving this problem despite the lack of assistance from BMWNA (fixated on fuel issue).