But some support surfaced amid spillover buying from a rally in wheat and from occasional short covering by funds and slow farmer selling.
Traders remained cautious amid persistent talk that index funds may soon buy corn futures as a long-term hedge against inflation.
CBOT corn closed 3/4 cent per bushel higher to 1/2 lower, with March up 3/4 at $2.16-1/4 per bushel.
Technical traders were focused on some signs the corn market was a bit overbought.
The nine-day relative strength index for March closed Tuesday at 75.
Traders view a reading of 70 or more as indicating an overbought market.
Technical support in the March contract was at $2.12-1/2 per bushel and resistance was at $2.18-1/4.
Exports were quiet overnight.
Traders remained a bit cautious amid news this week that Japan has begun mandatory inspections of all US food corn arrivals at Japanese ports for aflatoxin, after the cancer-causing mold was found in a shipment recently.
Cash basis bids for corn in the Midwest early on Wednesday were mostly unchanged as the market remained quiet following the Christmas holiday.
Oats futures closed unchanged to 3-3/4 cents per bushel higher, with March 3-3/4 at $1.97-1/2 per bushel.