As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTED THAT AFTER TAKEOFF, AT APPROXIMATELY 700FT AGL, THE CABIN ALTITUDE ON THE EICAS WENT TO DASHES. THE CREW DECIDED TO RETURN TO KDTW. DURING THE RETURN, AT APPROXIMATELY 300FT AGL, THE CABIN ALTITUDE RETURNED TO THE EICAS. THE AIRCRAFT LANDED WITHOUT INCIDENT. MAINTENANCE RESET THE CABIN PRESSURE ACQUISITION MODULE. OPERATIONAL CHECKS WERE GOOD WITH NO FURTHER DEFECTS NOTED.