As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IAH - FLT 2129 THE CREW REPORTED AMBER DASHES ON THE CABIN ALTITUDE RIGHT AFTER TAKE OFF. THE AIRCRAFT RETURNED TO IAH WHERE IT LANDED WITHOUT INCIDENT. MAINTENANCE INSPECTED THE AIRCRAFT, TIGHTENED A "B"-NUT ON THE SENSE LINE GOING TO THE ELECTRO PNEUMATIC OUTFLOW VALVE, OPERATIONALLY TESTED WITH NO DEFECTS, AND THE AIRCRAFT WAS APPROVED FOR RETURN TO SERVICE.