The engine issue had occurred on the first production representative development, preventing the A400M from participating in the Farnborough Air Show flying display.
Airbus Military said metallic chips had repeatedly been found in an engine oil system during function and reliability testing.
Airbus Military and engine manufacturer Europrop International found the chips were the result of a crack in a cover plate and didn't affect engine capabilities.
EPI has rectified the problem and a validation process for the solution is being conducted.
"As a consequence, the civil Type Certification and military Initial Operating Capability will now move into the first quarter of next year, followed by first delivery to the French air force in the second quarter of 2013," Airbus Military said. "Despite this we maintain the overall delivery plan of four aircraft in 2013."