As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SHIP 3916 -ATB/PRESS- RETURNED SLC DUE TO CABIN ALT. WARNING HORN AND PRESSURIZATION ISSUE ABOVE 10K FT. CORRECTIVE ACTION: PERFORMED DCPC BITE CHECK. NO FAULTS FOUND. REPLACED COCKPIT PRESSURE CONTROL PANEL AND OUTFLOW VALVE. OPS CHECKS GOOD.