As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING AUXILIARY POWER UNIT OPERATIONS PRIOR TO FLIGHT 2894 AT THE GATE, THE RAMP REPORTED WHITE SMOKE ENTERING C-4 AND STRONG FUMES WERE SMELLED THROUGHOUT CABIN. THE AIRCRAFT WAS REMOVED FROM SERVICE. PERFORMED LEAK CHECK AND NO LEAKS NOTED. THE OPERATIONAL CHECK WAS GOOD FOR NO SMOKE OR FUEL SMELL. NO PARTS REMOVED OR REPLACED. THE AIRCRAFT WAS RETURNED TO SERVICE.