As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER STARTING THE RT ENGINE & THE LT ENGINE IS OFF. THE RT VACUUM SYSTEM PULLED BOTH LT & RT ORANGE INDICATOR BULLETS ON THE VACUUM GAUGE INDICATING THAT THE LT VACUUM SYSTEM IS WORKING, BUT THE LT ENGINE IS SHUT DOWN. CAUSE: THE LT SHUTTLE/CHECK VALVE FOR THE WING DEICE BOOTS STUCK OPEN ALLOWING THE RT VACUUM PUMP TO SUCK DOWN THE LT SYSTEM THROUGH THE LT VACUUM PUMP GIVING A FALSE OPERATIONAL INDICATION.