What was found
AFTER DIVERT TO TWF, WE DEICED AIRCRAFT. WHILE DOING POST DE-ICE CHECKLIST, WHEN TURNING ON L PACK, SMOKE STARTED BILLOWING THROUGH COCKPIT AND CABIN. WHEN TURNING PACK OFF, SMOKE DISSIPATED. DEICING FLUID IN APU AIR INTAKE DETERMINED TO BE CAUSE OF SMOKE. C/W PROCEDURES LISTED IN A220 EFIM SOLUTION #1-8458 - ELIMINATION OF RESIDUAL ODORS WITH APU AS SOURCE. AFTER PROCEDURES COMPLETED, NO ODOR IN CABIN OR FLIGHT DECK. OK FOR SVC. (LP# 8160236)