As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFT CARGO FIRE DETECTION TEST DOES NOT WORK INTERMITTENTLY. GROUNDED - YES. PERFORMED CEU BITE PER B737-800 FIM 26-16 TASK 801. CEU FAULTED AFT CARGO PIT DETECTOR A3. REMOVED AND REPLACED DETECTOR A3 PER B737-800 AMM 26-16-01. PERFORMED CARGO BAY SMOKE DETECTION OPS TEST PER AMM 26-16-00-710-801 TEST PASSED.