D.C. police union president Larry Simons called off a threatened "no confidence vote" against Police Chief Burtell M. Jefferson yesterday after a 90-minute conciliatory meeting with Jefferson called by Mayor Marion Barry.

Jefferson, involved in an increasingly bitter dispute with the union over his policies, agreed to "open lines of communication" to union leaders, Barry said. Jefferson and Simons then held a separate, brief meeting at which they agreed to keep talking.

Barry brought the two men together yesterday after a week of turmoil in the department that followed Jefferson's decision to reinstate controversial Deputy Police Chief William Trussell to command of the department's major investigative units.

Sources close to Barry said he "made it clear" that Jefferson "is the chief" and that the mayor was tired of the department's public feuding, one of Barry's most nagging problems in his eight-month-old administration. "He said, Jeff's going to be around for a while," one union official said.

Barry told a press conference after the meeting that "Larry Simons and I disagreed over the Trussell affair. I support the chief."

Jefferson called the meeting "very positive" and Simons said it was a "very open and frank discussion," Simons also said he "felt much better" but added that police morale is still low.

Despite the public show of reconciliation, both union and police sources said afterwards, the racial antagonisms and command problems within the department aggravated by the Trussell affair will not be wiped away with only smiles and good intentions.

"If the union and Jeff have decided to take the first step toward conciliation, everybody should give it a chance to work and not go around trying to keep it (the controversy) going," one high-ranking police official said later. "What's been going on probably has had more effect on how the public views the department instead of our ability to fight crime. But the bickering doesn't help the department at all."

Trussell was cleared last week by a three-man panel appointed by Jefferson to investigate charges by homicide detectives that Trussell is incompetent and had made a derogatory racial remark. The panel voted 2 to 1 to transfer. Trussell because of the controversy, but Jefferson returned him as commander of the criminal investigations division. The union heatedly objected.

Later Trussell said he was considering suing some of the homicide detectives for libel, prompting further protests by the police union.

A spokesman for the mayor said yesterday that Turssell's threat to sue had been discussed at Barry's meeting yesterday but was not resolved. The spokesman said the decision was up to Trussell but that Jefferson had pledged "no reprisals" against the detectives.

Trussell and Assistant Police Chief Maurice Turner who was a member of the special panel Jefferson appointed, are scheduled to meet next week with homicide squad detectives to discuss their lingering grievances.

Barry said yesterday that he hoped the Trussell affair "could be put to rest" and that the department "can get back to the business of policing our city."

However, several police officials are known to be irritated with Trussell who they feel is a thorn in Jefferson's side and should retire now that he has been upheld.

Police officials also have expressed concern that the Trussell controversy has weakened their authority, possibly encouraging other complaint actions outside the department's paramilitary chain of command.

Barry said he expected to discuss police morale problems when he attends a three-day management seminar of police officials, which begins Sunday in Harpers Ferry, W. Va.

The Trussell controversy, which erupted in May when the homicide detectives publicly complained about the deputy chief, became a summer-long feud that raised fears among high police officials that the department's command structure was damaged.

It also ultimately heightened underlying racial tensions within the department as some black officials contended that the mostly white homicide squad was "using" the racial complaint against Trussell simply as a lever to remove him and embarrass Jefferson.

In addition, throughout the summer, Barry gave mixed signals to Jefferson, occasionally praising him publicly, but also making it clear he did not like the way Jefferson was handling the controversy or Jefferson's refusal to work with the union leaders.

The union gained Barry's support when it gave him an early endorsement for mayor last year and helped to erase Barry's image as a civil rights militant.

Early in Barry's term the union was openly saying that Barry had promised to replace Jefferson, a holdover department head from the slower paced days of Mayor Walter Washington. There were repeated news reports that Jefferson would soon retire, but all were denied.

As Barry and Jefferson reached for a working relationship, black police officials found themselves torn between their support for Jefferson as the first black chief of police and their support for the paramilitary command structure with the reluctant realization that Jefferson did not have clear control over his deparrtment.

"Despite appeals to him to be more visible, more powerful, more decisive, he continues" to shy away from problems and the press, one official said. One black official said his colleagues "are very uncomfortable over this."

Some white high-ranking police officials also are critical of Jefferson, saying he has not clearly indicated what future role they will play in the department, which is moving away from traditional control by white officers.

"This is entirely new," a top black official said yesterday. "The historic roles are entirely reversed. Blacks didn't know which way they were going and now whites don't know. We've got to utilize all our resources no matter what the color."

Ironically, the black officials, aware of and sensitive to their growing power, say they are fearful of making mistakes and feel constrained by the very blackness that whites now feel is limiting their own career choices within the department.