Politburo member Konstantin Chernenko returned to public view today, opening a meeting of the Soviet Communist Party Central Committee with an appeal for the "mobilization of spiritual energy of the population" to overcome the country's economic stagnation and other internal problems.

His speech to the 300-member policy-making body ended speculation that Chernenko was in serious political difficulties, but it contained repeated references to Soviet leader Yuri Andropov, who was described as "head" of the ruling Politburo, a phrase indicating Andropov's preeminence and Chernenko's role as a loyal team player.

Chernenko, who was the closest political associate of the late Soviet president and party leader Leonid Brezhnev, was Andropov's main rival for the post of general secretary of the Communist Party after Brezhnev died last year. Little has been heard of him in recent weeks, causing questions about his continued role in the leadership.

Although devoted to questions of ideology, the two-day Central Committee plenum also is expected to approve personnel changes, including the selection of a new president, a post left vacant by Brezhnev's death.

Andropov, who as general secretary and commander-in-chief of the armed forces already holds the two most important positions, reportedly is being urged to become the titular chief of state as well.

If Andropov, as a result of his apparent physical frailty, refuses to take the ceremonial post, observers here believe that Marshal Dmitri Ustinov, the defense minister, is the most likely among a few candidates to become president.

The formal selection of president was expected Thursday during a one-day session of the Supreme Soviet, or parliament.

But all major decisions here are made by the Central Committee, which normally meets twice a year. The 11-member Politburo is the key decision-making agency for the rest of the year acting on behalf of the Central Committee.

The ideological plenum and Chernenko's 11,000-word report largely focused on the Soviet economy and problems connected with it, underscoring an impression that Andropov was trying to use the forum to lay down ideological foundations for economic changes he is reported to be planning to introduce in the fall. The Soviet economy has experienced severe problems in food production and industrial productivity in recent years, and Andropov has made efforts to revive the economy, the keystone of his government.

Soviet ideology is almost a form of state religion in this society. Any significant changes in the economic or social fields require adjustments of the ideological framework. Such adjustments have to gain approval of either the Central Committee or the party congress, which is held every five years.

In his speech, Chernenko mentioned terms such as "workers' self-management" which have been taboo until recently. He also asserted that the Soviet economy is being held back "by the shortcomings of its economic mechanism."

He said that "the pace of our advancement and, of course, the strengthening of the country's defense capability depend in many ways on how we will be able to mobilize the spiritual energy of the population and raise their labor and social activities."

Chernenko said "a new type of economic thinking" was needed to encourage "initiative, socialist entrepreneurship, greater responsibility and creativity."

His speech also suggested a cultural tightening at home and called for a "broad attack of counterpropaganda" against the West and primarily against the United States. He reiterated Soviet charges that the Reagan administration was "pushing mankind toward nuclear catastrophe" and that it was engaged in a "psychological war" to destroy socialism.

It is by no means certain, even after a Central Committee endorsement, that the new leadership will be able to carry out its plans. The ideological adjustments made on such occasions, however, allow the leadership to push for changes.

During Brezhnev's years, there were only a few one-day ideological plenums that were largely perfunctory since Brezhnev's hallmark was stability and abhorrence of ideological adjustments.

The last two-day ideological plenum of major significace was held 20 years ago under Nikita Khrushchev and it was dominated by the Sino-Soviet dispute and the redefinition of Moscow's attitude toward China. Judging by signals emerging from the current plenum, its most important issue is the economy.

Chernenko's report singled out as the party's "most important task" instilling labor discipline "in every person" and inculcating in all "a clear awareness of the need for conscientious work."

Chernenko said that Andropov's insistence on improved "labor discipline" has produced results. Most economic indicators show a sharp upturn in the first six months of this year compared to declining figures for the past four years.

But he complained about the chronic problems of drunkenness, hooliganism, speculation and theft of state property and urged "the most vigorous struggle" against them. He said that the system's contradictions included "struggle between the new and the old" and cited among "negative tendencies" the existence of narrow institutional interests, parochialism, conservatism and bureaucratic tendencies.

"Our advancement is restrained by shortcomings in the economic mechanism, by labor productivity particularly in agriculture that does not satisfy us, and by the insufficient civic maturity and discipline of a part of the population."

He singled out young people entering the labor force. Although "well prepared occupationally," he said, some young people show "delayed civil maturity, political naivete and sponging attitudes." He said "our enemy" is trying "to exploit for its ends the specific features of youth psychology" and this is why "it is necessary" to pay greater attention to the ideological "and work maturing" of the young.

Chernenko sharply criticized Soviet scientific institutions for their ivory tower mentality and attacked the Soviet media for its cliche dispatches and commentaries "in which you will not find either deep generalizations or fresh thoughts."

He said the Soviet party must increase "the offensive nature of our entire propaganda" and called on the arts to propagate the party line. It was not immediately clear whether he was urging a new crackdown against liberal and avant garde elements in the arts and theater. He criticized "certain film-makers and authors" for dealing with "unhappy destinies, troubles of life, loose and whining characters." The Ministry of Culture, and other Soviet organizations running the world of arts, theater, publishing and movies should vigorously step in to supervise things, he said. "There should be no room for either formalism or lack of control here," he added.

"The battle of ideas on the international scene is going on without respite," Chernenko said. "We will continue to wage it vigorously and with dignity."