Narrative:

Left ZZZ with #2 generator deferred. While in cruise flight; APU oil temperature caution message came on. Ran QRH and directed to land at nearest suitable airport. Called maintenance and dispatch and decided on ZZZ1. Declared emergency and landed without incident. Only way to prevent situation in the future is to not fly with a generator deferred.

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Original NASA ASRS Text

Title: DISPATCHED WITH AN INOPERATIVE GENERATOR; CARJ DIVERTS TO NEAREST SUITABLE ARPT WHEN APU OIL TEMPERATURE CAUTION MESSAGE ILLUMINATES.

Narrative: LEFT ZZZ WITH #2 GENERATOR DEFERRED. WHILE IN CRUISE FLT; APU OIL TEMP CAUTION MESSAGE CAME ON. RAN QRH AND DIRECTED TO LAND AT NEAREST SUITABLE ARPT. CALLED MAINT AND DISPATCH AND DECIDED ON ZZZ1. DECLARED EMER AND LANDED WITHOUT INCIDENT. ONLY WAY TO PREVENT SITUATION IN THE FUTURE IS TO NOT FLY WITH A GENERATOR DEFERRED.

Data retrieved from NASA's ASRS site as of May 2009 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.