As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DEICE PRESS CAUTION CLIMBING OUT OF SEA. PRESSURE DOWN TO 12 PSI DURING TAIL SECTIONS. DIVERTED. LANDING UNEVENTFUL. REMOVED FROM SERVICE. PERFORMED TACTILE INSPECTION OF INFLATED BOOTS ON TAIL SECTIONS, NO LEAKS FOUND. R&R LH LOW PRESSURE WARNING SWITCH AS A PRECAUTION, IAW Q400 AMM 30-11-31-000/400-801 OPS TEST PASSED. NO FURTHER DEFECTS NOTED. PER MOM A/C IS CLEARED FOR RETURN TO SERVICE.