Engineers from the Toyota Technical Center - located south of Ann Arbor - are now playing an active role in the Japanese automaker’s efforts to fix the sudden acceleration issue associated with its recalled vehicles, an executive confirmed today.

Toyota’s 1,100-person York Township engineering operation is playing an increasingly visible role in the automaker’s coordinated effort to debunk claims that the sudden acceleration issue is connected to electronic throttle control systems or software problems with its vehicles.

Kristen Tabar, general manager of electronics systems for the Toyota Technical Center, today participated in a high-profile demonstration for media in California, where Toyota engineers sought to discredit claims about the role of electronic throttle control problems in the sudden acceleration incidents.

Tabar also said today that Toyota is about halfway through a four-year project to construct an vehicle-size electromagnetic testing chamber at the Toyota Technical Center. She said Toyota can conduct electromagnetic testing on individual parts, but not entire vehicles, in York Township.

Her participation in today’s media briefing comes as Bruce Brownlee, senior executive administrator for external affairs at the Toyota Technical Center, told AnnArbor.com today that local engineers are now participating in the Japanese automaker’s efforts to fix the sudden acceleration issue.

Brownlee maintained Toyota’s previous statements that the Toyota Technical Center had nothing to do with the problems associated with the recall. He said the issues originated from the automaker’s Japanese operation.

“We are supporting the various investigations that we’re conducting,” Brownlee said.

Toyota today gathered a group of engineers and external experts for a Webcasted media briefing to discredit findings aired by Southern Illinois University Professor David Gilbert on ABC was illegitimate. Gilbert also shared his findings in Congressional testimony last month.

Gilbert’s assertions caused concern that the sudden acceleration problem was connected to the defects in the vehicles’ electronic throttle control systems. Toyota has maintained that the problems were related to sticky accelerator pedals or floor mat problems.

But engineers argued in the Toyota briefing that Gilbert had artificially “rewired” circuits in the Toyota Avalon he tested. The sudden acceleration issue Gilbert demonstrated on ABC is not something “that might actually occur in a car,” said Chris Gerdes, a mechanical engineering professor and director of the Center for Automotive Research at Stanford University.

“I am concerned that these misinterpretations are driving public fear and public policy,” Gerdes said. “You cannot rewire a circuit and expect it to behave as it was originally designed.”

Taber added: “It’s not even a realistic, real-world” scenario.

Still, doubts persist - and Toyota executives acknowledged in today’s media briefings that they cannot fully rule out the possibility that software issues or electronic throttle control are at fault.

Bruce Belzowski, assistant research scientist for the University of Michigan’s Transportation Research Institute, said he was unsure whether electronics were the root cause of the acceleration problems.

Belzowski said Toyota’s decision to publicly condemn Gilbert’s study was a bold move that could alternately soothe public concern or backfire.

“As a company, if you’re very confident in what you’re doing and you see people making what you think are false claims, calling them out on it’s not a bad idea,” Belzowski said.

But Belzowski emphasized that the sudden acceleration problems have always been notoriously difficult to diagnose, regardless of the automaker.

“This happens to be one of the more difficult problems that companies face,” Belzowski said.

Contact AnnArbor.com’s Nathan Bomey at (734) 623-2587 or nathanbomey@annarbor.com or follow him on Twitter. You can also subscribe to AnnArbor.com Business Review's weekly e-newsletter or the upcoming breaking business news e-newsletter.