As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT CREW REPORTED THAT AT THE GATE, ON ENTERING THE ACFT A STRONG CRAYON ODOR WAS NOTED, ALONG WITH A MILD BURNING OF THE EYES . THE CABIN CREW SHOWED UP 10 MINUTES LATER AND EXPERIENCE SAME ODOR IN CABIN. AIRCRAFT WAS GROUNDED. MAINTENANCE SUSPECTED THE APU IS LEAKING OIL FROM THE TURBINE SHAFT BUT ADDITIONAL TROUBLESHOOTING IS REQUIRED. MAINTENANCE REPLACED APU IAW TASK CARD.