The Yaounde victory sealed first place in Group I for the ´Indomitable Lions´, who finished four points clear of their opponents.[break]
Chedjou, who recently signed a four-year contract with Turkish club Galatasaray, netted three minutes before half-time.
A draw would have been enough for six-time World Cup qualifiers Cameroon while Libya needed maximum points to keep alive their dreams of a first appearance.
Libya set the pace for much of a six-round mini-league that began in mid-2012, but Togo did them no favours last June.
The Togolese fielded a suspended iplayer in a 2-0 win over Cameroon, who were awarded a 3-0 victory and three points.
Instead of facing Libya in second place two points adrift, the ´Lions´ had a one-point lead and home advantage at Stade Ahmadou Ahidjo.
Cameroon were the last nation to reach the play-offs, joining Algeria, Burkina Faso, Cape Verde, Egypt, Ethiopia, Ghana, Ivory Coast, Nigeria and Senegal.
A seeded draw, based on the latest FIFA rankings, will be made on September 16 in Cairo.
And the winners of five two-leg ties scheduled for October and November will go to Brazil.
Kenya ended a five-match win drought in the qualifying competition by edging visiting Namibia 1-0 in Nairobi.
Defender David Owino scored after five minutes to give the ´Harambee Stars´ maximum points from their final mini-league fixture.
The result meant a change of positions in the final standings with Kenya climbing to third and Namibia dropping to last place.
African champions Nigeria won Group F on Saturday by defeating Malawi 2-0 in Calabar as they look to qualify for their second straight World Cup after going out in the first round in South Africa.
Zimbabwe and Mozambique drew 1-1 in Harare, leaving the southern Africa neighbours winless after six Group G matches each.
Captain Masimba Mambare put the home side ahead just before half-time and substitute Maninho levelled on the hour mark.
Egypt were runaway winners of the group and complete their schedule Tuesday at home to second-placed Guinea in El-Gouna. Mozambique finished third and Zimbabwe last.
Related story
Overloaded train derails in Cameroon, killing at least 53
