As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) DURING PUSH BACK FROM THE GATE, FLAP LEVER WAS MOVED TO 8 DEGREES BY THE FLIGHT CREW BUT THE FLAP DIDN`T EXTEND AND "FLAP FAIL" CAUTION MESSAGE APPEARED ON THE ENGINE INDICATION AND CREW ALERTING SYS (EICAS). THE ACFT WAS TOWED BACK TO THE GATE. FLAP ELECTRONIC CONTROL UNIT (FECU) FAULT CODES WERE RETRIEVED AND DECISION WAS MADE TO REPLACE THE RT BRAKE POSITION SENSOR UNIT (BPSU). THE UNIT WAS REPLACED AND THE ACFT RETURNED INTO SERVICE.