As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER APU START UPON LANDING, SIGNIFICANT ODOR/FUMES THROUGHOUT ENTIRE CABIN. SMELLED LIKE BURNING PLASTIC.T/S PER A220 EFIM SOLUTION #1-8458 & WC 0550-2001. FOUND ODOR PRESENT WITH APU RUNNING. C/W WC 0550-2001. C/W ENGINE RUNS. ALL PARAMETERS CHKS NML. NO ODOR PRESENT WITH ENGS OPERATING. R/R LT & RT RECIRC PER A220 BD500-A-J21-22-03-01AAA.