FIFA said Maradiaga, a Honduran who played for his own country in the 1982 World Cup, had "allowed and failed to report" a meeting in which a third party offered the players "financial compensation" in exchange for fixing the result.
It said the offer was rejected and reported by the players in a news conference on Sept. 5, 2016. The incident was widely reported at the time.
Maradiaga could not immediately be reached for comment.
El Salvador were bottom of their four-team group with two points from five games and had already been eliminated from the competition for places at this year's finals in Russia.
However, a heavy defeat for El Salvador could have potentially allowed Canada to finish above Honduras and progress to the next stage of the competition on goal difference.
In the event, Canada won 3-1 but were eliminated after Honduras drew 0-0 away to Mexico.
Maradiaga, 63, was found guilty of violating FIFA ethics rules on bribery and corruption and duty of disclosure, FIFA said in a statement. He was also fined 20,000 Swiss francs (14,738 pounds).
He is widely known in Central America, having also coached the national teams of Honduras and Guatemala as well a number of clubs including Marathon, Motagua, Real Espana and Aguila.
Central America is seen as especially vulnerable to match-fixing as many clubs struggle financially, playing conditions are poor and players often do not get paid on time.
In 2013, El Salvador banned 14 international players for life for match-fixing, including some of their best-known and most experienced names.
(Writing by Brian Homewood in Bern; Editing by Ken Ferris)
