As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) DURING CRUISE NR 1 ENGINE FADEC A FAULT, FADEC B FAULT. ENGINE CONTINUED TO OPERATE NORMAL EXCEPT IN DESCENT NR 1 ENGINE HAD MOMENTARILY SMALL EXCURSIONS TOWARD IDLE (APROX 21. N1 DROP) AND IDLE WOULD ANNUNCIATE EVEN WHEN IDLE NOT REQUIRED. REPLACE ECU NR 1 ENGINE AS PER AMM 73-21-60-400 ENGINE RUN-UP C/O NO FAULTS, CONSIDERED SERVICEABLE.