Diesels don't require spark, but modern diesels use electronics for fuel injection, fuel pump, drive-by-wire throttle, engine monitoring, and so on. Since at l

Diesels don't require spark, but modern diesels use electronics for fuel injection, fuel pump, drive-by-wire throttle, engine monitoring, and so on. Since at least the ~2000 era, a VW diesel will run with no alternator (for a while) but not without a battery.