As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE IN CRUISE, CREW RECEIVED ENG ADPT HEAT 2 CAUTION ENG INTAKE HTR ADVISORY LIGHT WENT OUT AT THE SAME TIME. RETURNED TO FIELD. LANDING UNEVENTFUL. REMOVED FROM SERVICE. FOUND "INTAKE LIP HTR ENG 2" CIRCUIT BREAKER POPPED. PUSHED C/B IN, CLEARED CDS FAULT REF GPM 9.2.2.1. PERFORMED ENGINE AIR INTAKE ANTI-ICING OPS TEST REF Q400 AMM 30-21-00-710-801. OPS CHECK GOOD. NO FAULTS RETURNED. CLEAR DEFECT, NO OTHER DEFECTS NOTED. RETURNED TO SERVICE. NO PARTS REPLACED.