Former Fairfax County school psychologist Arthur S. Pomerantz was arrested by Montgomery County police yesterday on a fugitive charge after he failed to surrender to Fairfax police on a second charge of child sexual abuse.

The 46-year-old Pomerantz has become the center of a controversy in Fairfax since he was arrested Aug. 16 on a charge of sexual battery involving a school-aged boy. County school officials have said they are troubled over why he was allowed to return to the county schools after being suspended in 1981 when police from Prince William County raised questions about whether he was involved in a sex act with a minor there.

Pomerantz has said he is innocent of that charge and yesterday he failed to surrender to Fairfax police on the second warrant, which Montgomery police spokesman Sgt. Harry E. Geehreng said charges him with committing sodomy with a juvenile under 13. Pomerantz was arrested without resistance at 3:20 p.m. at his brother's home in Potomac, Geehreng said.

Pomerantz's Falls Church roommate, Edward C. Buss, 42, also was arrested yesterday on a Fairfax charge of committing sodomy with another juvenile under 13, Fairfax police said. That charge stemmed from an alleged incident on May 7, 1983.

Buss, who was held on $25,000 bond at the Fairfax County jail, was arrested at the Arlington firm where he worked as a computer technician.

Fairfax County police said the new charge against Pomerantz stemmed from an incident on April 30, 1983, when he worked for the county schools. The youth involved in that charge, now 15, called police after reading newspaper accounts of Pomerantz's arrest, according to Police Lt. David R. Franklin, who heads the department's child services section.

After a hearing before a Montgomery District Court commissioner, Pomerantz was held without bond in the Montgomery County Detention Center pending an extradition hearing today. A woman who identified herself as Phyllis Pomerantz said the family has no comment on the arrest.

Pomerantz was arrested Aug. 16 on a sexual battery charge stemming from an alleged incident on July 15. Police said three youths are involved in the three separate charges pending against Pomerantz and Buss.

Pomerantz was a psychologist with the Fairfax schools from 1965 until last year, when he was forced to resign after twice being placed on administrative leave after allegations that he had committed sexual acts with young boys.

Police said the two boys involved in yesterday's arrests were Fairfax students who met Pomerantz because they also lived in the Falls Church area. Although Pomerantz did not know the youths through school, "he did use the fact of his position and what he did to gain the confidence of the victims," police spokesman Warren Carmichael said.

Fairfax School Superintendent Robert R. Spillane has said he has ordered his staff to conduct an investigation into why Pomerantz was allowed to remain a school employe and how to assure that an employe accused of misconduct can be disciplined in the absence of criminal charges.

Police sources have said they were mystified about how Pomerantz remained a school employe after the investigators provided photographs they said showed Pomerantz engaged in a sex act with a youth. Prince William police said they did not press charges against Pomerantz in 1981 because they could not state when the alleged act occurred.