A key victory for victims’ lawyers in late October may give plaintiffs extra ammunition in their fight against Toyota  when lawyers head to U.S. District Court in Santa Ana in March to argue claims that Toyota vehicles accelerate without warning.

Toyota had cruised to three consecutive wins in unrelated unintended-acceleration liability lawsuits until an Oct. 25 jury verdict in Oklahoma ordered Toyota to pay $3 million in damages to the families of Jean Bookout and a passenger in her 2005 Camry, Barbara Schwarz. Toyota settled for an undisclosed amount of punitive damages before the jury could finish deliberations.

A piece of testimony in the Bookout case may play a key role in the bellwether California case, filed by the estate of Ida Starr St. John. The testimony of embedded-software expert Michael Barr, based on an 800-page report, purports to show that Toyota software is prone to error and could lead to a malfunction in vehicle electronic throttle control systems.

Toyota contends the Bookout jury verdict was not based on unintended acceleration but on several other factors — including pedal clearance above the floor mats and the lack of a brake override system. By settling before the jury could return punitive damages, jurors were not polled to determine specific reason for the monetary award.

Intriguingly, both the plaintiffs and Toyota believe that Barr’s testimony can help win their case.

Plaintiffs’ lawyers contend Barr’s “ghost in the machine” theory debunks joint studies by Toyota, NHTSA and NASA that could find no glitches in Toyota’s software source code. Barr’s analysis states that Toyota fail-safes do not reliably detect frequent software malfunctions.

Barr’s company, Netrino LLC of Elkridge, Md., was paid by plaintiffs’ lawyers to perform the research.

Toyota likely will counter that Barr’s theory is speculative. Under cross-examination in the Bookout case, Toyota counsel Randy Bibb attempted to corner Barr into admitting that, when detected, the software glitches always triggered fail-safe systems.

In his testimony, Barr insisted that fail-safes often took seconds, if not minutes, before activating.

Barr testified that fail-safes sometimes occurred only if a test driver took counterintuitive action, such as lifting a foot off the brake pedal. Barr admitted that the acceleration events he chronicled only happened when caused by external software prompts, but that consumer complaints to NHTSA validate real-world instances. Barr testified that, in his testing, “task death” exists in Toyota’s software coding — a situation he says can result in a loss of throttle control.

Said Toyota spokeswoman Carly Schaffner: “Despite nearly three years of litigating this case and unprecedented access to Toyota’s source code, plaintiff’s counsel have never replicated unintended acceleration in a Toyota vehicle and have failed to demonstrate that any alleged defect actually caused the accident at issue in this case. The bottom line is that there are no real-world scenarios in which Toyota electronics can cause a high-speed unintended acceleration event.”

With the St. John case, Judge James Selna has limited Barr to testifying whether a specific software defect can be linked conclusively to that specific accident.

Another twist in the protracted legal battle: Ida Starr St. John has died since giving her initial testimony, but Selna has allowed that testimony to stand. Her death was not related to the 2009 crash of her 2005 Camry. The trial was scheduled to start Tuesday, Nov. 5, but a continuance was granted late last week until March 2014.

A separate class-action lawsuit in Selna’s court alleged economic losses of Toyota owners stemming from acceleration issues. In July, Toyota settled in a $1.6 billion payoff to resolve those claims, which did not include personal injury or wrongful death lawsuits.

The Bookout case was the second time Toyota has paid a settlement when a ruling appeared to be going against it. In 2010 Toyota paid a $10 million settlement — without admitting liability — to the estates of a California Highway Patrol officer and three occupants killed when their Lexus ES sedan lost control near San Diego.

These settlements run counter to a proclamation made last year by Toyota chief counsel Chris Reynolds. While acknowledging that every person or company has a dollar-figure that will trigger a settlement, Reynolds said, “I’m not exactly in the position to compromise with anybody over that issue. … We’re just not going to do it.”