New-car and truck owners who have a complaint with the dealer can now look forward to a more systematic way of resolving their problem through improvements announced yesterday in AutoCAP, the nationwide system of mediation panels.

The changes amount to "a major step in addressing one of the most expensive, annoying and frustrating problems we have today -- auto consumer complaints," said Esther Peterson, special assistant to the president for consumer affairs, at a press briefing at the Old Executive Office Building. c

"Auto-related problems consistently lead the list of recorded complaints to every type of complaint handling organization -- both within the government and in the private sector," she said.

Peterson said that two years ago she asked the dealers' association "to up-grade its consumer-complaint mediation process. "I am delighted to announce today that NADA has adopted many of the recommendations, and, hopefully, consumers will soon be seeing beneficial effects from these new standards."

The improvements involve standardizing the operating procedures of the panels, including the requirement that at least 50 percent of the members on any mediation panel be consumer representatives.

AutoCAP-the Automotive Consumer Action Program -- was begun in 1973 by the National Automobile Dealers Association, and about 21,000 of the nation's 26,000 dealers belong. Up to now, panels, sponsored by local dealer associations, have differed in their programs, causing confusion among consumers. The major auto manufacturers also have begun establishing or are considering consumer appeals boards.

Present AutoCAP programs must comply with the new standards within a year. Some including the one sponsored locally by the Automotive Trade Association of the National Capital Area, already operate under these new procedures.

Other new features:

Participating dealers are to be bound by the decision of the mediation panels, but consumers can accept or reject the decision, taking their case to court if they feel it necessary.

Each local AutoCAP is "encouraged" to seek members from "all sectors of the community" and to consider "recognized local consumer spokespersons for appointment to the panels."

Public observers, including the press, are to be invited to panel meetings.

Local AutoCAPs are to be required to "publicize and promote" the program to dealers and the general public. "too often people don't know what is available to them," said Peterson.

Dealer permission to use the AutoCAP name is to be "subject to annual recognition and endorsement."

Peterson stressed that the national association must now "begin a major effort to get franchised dealers to participate in AutoCAPs comply with the new standards."

Barbara G. Gregg, executive director of the Montgomery County Office of Consumer Affairs and a consumer representative on the committee writing the new procedures, and she believes they satisfy the requirement that consumer-complaint mechanisms be "visible, accressible, speedy, fair and conclusive."

If a new-car or truck buyer has a complaint with a participating dealer that the two cannot resolve, the buyer can call the local AutoCAP office. (In Washington, the number is 657-3200).

A short questionnaire is sent out on which the buyer outlines the complaint.

When AutoCAP receives it, the dealer is given a chance to respond within a time period, such as a week.

If the AutoCAP staff cannot help in reaching agreement then the problem goes to the panel. In Washington, the panel includes five dealer representatives from city and county agencies, who meet about once a month.

One of the panel members investigates the dispute and may talk with the buyer and the dealer. In some cases both may appear before the panel. A decision is reached by majarity vote.

George B. Rose, chief of the automotive division of the Montgomery County Office of Consumer Affairs, who sat on the local AutoCAP panel in 1977 and 1978, said yesterday he found the operation "very fair to the consumer."

Most of the complaints, he said dealt with warranty questions such as whether a particular part or service was included in the warranty contract. Other complaints involved "bumping," in which a dealer would sign a new-car contract at one price and later tell the customer the price had gone up.

In those cases, said Rose, the panel ruled "the customer got the car at the first price." Very few cases were so clear cut, though, he said. In "the vast majority a fair answer lay in between" what the dealer and the buyer maintained.

Rose, who was panel vice chairman in 1978, said he found the dealers on the panel often were tougher on the dealers whose cases they heard than the panel's consumers representatives. They particularly "looked hard," he said, at practices that, although legal, might not be entirely ethical.

Gerry Murphy, director of the Washington AutoCAP program to which about 90 percent on the area's dealers belong, says his office receives about 2,000 calls and letters a year, and in most cases his staff is able to help the parties reach an agreement. Only about 5 percent must be referred to the panel, although the panel reviews all actions the staff taken, he said.

One weakness in the AutoCAP program, noted Rose, is that it addresses only individual complaints. A dealer might lose a case before the panel, but repeat the same violation with another customer who doesn't complain.