As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: FLIGHT DIVERTED TO BNA ON ACCOUNT OF APU SHUT DOWN AND NUMBER TWO GENERATOR ON PLACARD. AN EMERGENCY WAS DECLARED. MAINTENANCE REMOVED AND REPLACED THE #2 ENGINE GCU IAW AMM 24-22-34. OPS CHECK OK. REMOVED AND REPLACED LOW OIL PRESSURE SWITCH IAW AMM 49-94-14. OPS CHECK OK. (SEE SDR # AALA201909189019)