As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
TOXIC ODOR IN AIRCRAFT THAT IS MORE PREVALENT IN THE COCKPIT. THE PREVIOUS FLIGHT CREW REPORTED THE ODOR STARTED ON TAXI INTO GATE. AIRCRAFT WAS GROUNDED. ACCOMPLISHED CARDS 26L00021001 AND 26L00021002. FOUND THE APU TO BE SOURCE OF THE ODOR. REPLACED APU IAW 26L31049C03. OPS GOOD.