An attorney who is the son of a federal judge in Texas has withdrawn from a class action lawsuit over allegedly fast-running odometers after The New York Sun raised questions about the propriety of his involvement.

T. John Ward Jr. of Longview, Texas, made the request to back out of the case over Nissan automobiles on Monday, shortly after the Sun asked him for an interview and spoke with one of his co-counsel about whether the case might benefit from rulings by Mr. Ward’s father, Judge T. John Ward, who is presiding over a nearly identical case against Honda in the same judicial district.

The younger Mr. Ward’s motion does not specify any reason for his withdrawal. He did not return messages from the Sun. In response to an interview request, Judge Ward said he could not comment on pending litigation. Legal academics contacted by the Sun before the younger Mr. Ward pulled out offered varying assessments of whether his presence on the Nissan case required his father to step aside from the similar case involving Honda and many of the same plaintiffs’ lawyers.

“He’s required to recuse himself,” a professor of legal ethics at Hofstra University, Monroe Freedman, said. “The rules very clearly recognize a connection between a judge and somebody in his or her immediate family.”

A professor of law at New York University, Stephen Gillers, said Judge Ward’s rulings in the Honda case, while not binding precedent, could have a significant effect on the judge handling the Nissan case. “To another judge in the same district, it does have some persuasive force,” Mr. Gillers said. “This is not a bull’s eye on recusal. It’s a little bit off center. … It’s a close one.”

A law professor at Northwestern University, Steven Lubet, punted, calling the question “highly fact intensive and contingent.”

One of the lawyers who brought both suits, David Miller of Addison, Texas, said Monday that he saw no conflict in having the younger Mr. Ward on the Nissan case. “We don’t think it raises any questions,” Mr. Miller said. “We haven’t had anybody raise that.” Mr. Ward, 37, attended Texas Tech law school and initially focused on personal injury cases. Aside from the Nissan matter, his current array of cases before the federal court consists almost entirely of patent infringement actions. Marshall, population about 24,000, has become a mecca for patent litigation because of the attitudes of local juries and, in some part, the legal rulings of Mr. Ward’s father.

Asked why the younger Mr. Ward was retained for the Nissan case, Mr. Miller said, “He was brought in because he works as local counsel. … Johnny Ward practices in the Eastern District all the time.” Pressed further, Mr. Miller said, “I’m not going to discuss Mr. Ward’s practice anymore.”

The Honda lawsuit, which claims that the odometers record between 2% and 4% more mileage than the vehicles travel, was filed in April 2004 by four attorneys: Mr. Miller, Jay Kutchka of Fort Smith, Ark., James Holmes of Henderson, Texas, and R. Stephen Woodfin of Kilgore, Texas. In November 2006, the four attorneys brought a similar case against Nissan, alleging that its odometers were set to overstate mileage by at least 2%. The case was filed in Marshall, Texas, and stood a 70% chance of being assigned to Judge Ward under local rules. However, the docketing system placed it with Judge David Folsom in nearby Texarkana. About six weeks later, T. John Ward Jr. notified the court that he was joining the team of plaintiffs’ lawyers pursuing the Nissan case. If he had been listed on the case at the outset, his presence would have prevented the case from being assigned to Judge Ward, who is automatically recused from cases involving his son. However, the order does not affect his son’s ability to practice before other federal judges in the same district.

The possibility that decisions made in the Honda case could affect those in the Nissan case is more than theoretical.

In papers filed earlier this month, the lawyers in the Nissan case asked Judge Folsom to take judicial notice of Judge Ward’s ruling appointing them as interim counsel for the car owners affected by the Honda suit. “The experience garnered by Counsel over the course of three years of litigation in that case will serve the interests of the Womack class well,” the attorneys wrote, referring to the Nissan owner named as a plaintiff in the case, Rebecca Womack.

The younger Mr. Ward’s name appears as one of the lawyers “of counsel” on the motion, which twice mentions his father.

Messrs. Kutchka, Holmes, and Woodfin did not return calls seeking comment for this article. In recent days, Judge Ward has moved aggressively to conclude the Honda case. Last week, he held a hearing on a proposed settlement under which the carmaker would extend warranties, service contracts, and lease-related mileage limits on some cars while offering payments for some repairs that were not covered by warranties. Several lawyers traveled to Judge Ward’s courtroom in Marshall to object on the grounds that the deal would not properly compensate Honda owners who had already sold cars or might sell them in the future. A day after last week’s session, Judge Ward ordered all the lawyers to return to Marshall, which is about 150 miles east of Dallas, to attend a mediation today before a federal magistrate. The judge also ordered that the Honda owners represented by the objecting lawyers appear in person. When an Arizona attorney who came to last week’s hearing to object on his own behalf, Dale Robinson, cited a scheduling conflict and complained about the cost of returning to Texas, Judge Ward was not sympathetic. “He has not demonstrated that he would suffer a significant burden in increased costs by attending,” the judge wrote, refusing Mr. Robinson’s request to delay the mediation or attend by phone.

An attorney who has objected to numerous class actions settlements but is not involved in the Honda case said Judge Ward’s order was unusual and seemed intended to ease a deal by discouraging objectors. “Requiring the client to actually fly to do that? I’ve never heard of that one,” the lawyer, Lawrence Schonbrun, said. “It’s harassment to the objectors, in my mind. It shouldn’t be allowed.”

While some have bristled at Judge Ward’s apparent haste to resolve the Honda case, he is known for his efficiency. The judge, 64, who was appointed in 1999 by President Clinton, boasts of keeping a “rocket docket” and sometimes runs a chess clock on lawyers in his courtroom, a local attorney said.

The attorneys in the Honda case are asking Judge Ward to award them $9.5 million in legal fees, which Honda and other defendants have agreed to pay. No settlement or fee request has been filed in the Nissan case.