James Avery Death Certificate -- Severe Medical Problems Before Death

James Avery -- who played Uncle Phil on "Fresh Prince of Bel Air -- was suffering from several major medical problems for years before he died from complications following an open heart surgery, TMZ has learned.

We've obtained the death certificate, filed in L.A., which shows the 68-year-old suffered from severe coronary heart disease -- along with end-stage kidney disease and type-2 diabetes.

Avery's official cause of death is listed as cardiorespiratory arrest -- which basically means his heart stopped.

TMZ broke the story, Avery passed away in a Glendale, CA hospital on Dec. 31 -- roughly 7 weeks after undergoing a bypass surgery in the wake of a heart attack.

The death certificate also says Avery was cremated and his remains were scattered at sea off the coast of L.A.