for the 750iL guys...the 'voltage out of range' fault described is USUALLY a lean condition on M70's caused by leaking intake runner to cyl. head sealing blocks. hard to diagnose w/o good equipment BUT if you begin with a cold engine & have that center engine cover off for access, with it idling spray some carb cleaner around the injectors & intake-cyl. head area.....if the idle smoothes out or increases a little, you've found your problem. NOTE: this is though to recognize on a V-12 but it's all you can do W/O an Infra-Red Analyser.