As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) ON START-UP THE INLET BARRIER FILTER SYS WOULD NOT TEST ON THE LT SIDE. A FAULT WAS INDICATED ON THE CONTROL PANEL FOR IBF. THROUGH TROUBLESHOOTING IT WAS DISCOVERED 1 OF THE 2 DIFFERENTIAL PRESSURE SENSOR WAS DEFECTIVE. THE PART WAS REPLACED WITH NEW AND FAULT CLEARED.