As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON CLIMB DE-ICE PRESS CAUTION ILLUMINATED. WOULD CYCLE THROUGH TO LEFT OUTBOARD BOOT WOULD NOT DEFLATE ON "SLOW" OR "FAST" BUT WORKED IN MANUAL MODE. DIVERTED AND ACCOMPLISHED AN UNEVENTFUL LANDING. REMOVED FROM SERVICE. C/W DETAILED INSPECTION OF DE-ICING BOOTS, IAW Q400 AMM TASK 30-11-00-280-802 STEPS (1-4). C/W DETAILED INSPECTION OF DE-ICE BOOTS, IAW Q400 AM 30-11-00-280-802 STEP 5. REPLACED LEADING EDGE AND DDV NR 6 REMOVAL AND REPLACEMENT. DE-ICE CAUTION LIGHT DID NOT ILLUMINATE. RETURNED TO SERVICE.