As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SEA FLIGHT 2316: AFTER START, NR 1 AND NR 2 DEICE PRESS GAUGE INDICATES 14 PSI. MAINTENANCE GROUND RAN NR 1 AND NR 2 ENGINES AND C/W OPS CHECK OF THE A/F DEICE SYSTEM IAW Q400 AMM TASK 30-11-00-720-801. BOTH NR 1 AND NR 2 DEICE PRESS GAUGES READ 18 PSI. NO PARTS REPLACED. AIRCRAFT RETURNED TO SERVICE.