As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIR TURNBACK, AUTO FAIL LIGHT ILLUMINATED ALONG WITH ALT LIGHT. MOVED THE PRESSURIZATION MODE SELECTOR TO ALT MODE PER THE QRH THE AUTO FAIL LIGHTS KEEPS ILLUMINATED. WENT TO MAN MODE IN ORDER TO CONTROL THE CABIN. R&R NR 1 DIGITAL CABIN PRESSURE CONTROLLER