As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SMOKE DETECTOR FAULT DISPLAYED ON UPPER ECAM. REPLACED AFT PIT SMOKE DETECTOR 6WH. NO HELP, BOTH CHANNELS FAILING DIFFERENT SMOKE DETECTORS EACH TIME TESTED. SLAVED IN KNOWN GOOD DETECTOR NO HELP. TRIED NEW SDCU NO HELP. RE-INSTALLED ORIGINAL SDCU. REF TSM 26-16-0 0-810-819-A AND 26-17-00-810-803-A SDCU DOUBLE CHANNEL FAULT.