Class action specialist Tony Merchant says the Pontiac Vibe and the Toyota Matrix are 'veritable twins.' (Associated Press)

A Canadian class action lawsuit filed against Toyota and New United Motor Manufacturing Inc. has expanded to include the GM-branded Pontiac Vibe.

The lawsuit was launched by Regina class action specialist Tony Merchant, who has alleged that Toyota's electronic throttles in the Vibe are defective. The suit focuses on those throttles and lists the plaintiff as Ed Harris of Salt Spring Island.

New United Motor Manufacturing Inc., based in Fremont, Calif., was a joint venture between Toyota and GM until June 2009, when GM pulled out. Toyota has announced its intention to close the plant April 1 to cut costs.

"Although branded differently, the Pontiac Vibe and Toyota Matrix are veritable twins. The Pontiac Vibe is manufactured at the Toyota plant in Fremont, California," according to a statement filed Tuesday in British Columbia Supreme Court.

Toyota continues to insist that the electronic throttle is not a cause of sudden acceleration.

On Tuesday, Toyota's executive vice-president Takeshi Uchiyamada told a U.S. Senate Commerce Committee that Toyota has sold over 40 million vehicles with electronic throttle control and "there's not a single case where it could identify the electronic throttle control as the cause of unintended acceleration."

The Japanese automaker has maintained that the problem is related to floor mats or to mechanical wear on the accelerator pedal and has recalled 8.5 million vehicles globally to fix the problem.

None of the allegations in the lawsuit has been tested in court and the suit has not been certified. It must be approved by a judge before it can proceed to any sort of trial.

Merchant said there are about 28,000 of the Pontiac Vibes in Canada, from the model years 2009 and 2010.

"It's not a solvable problem because you have to put in a new system and the only way to put in a new system would be to get all these things back to the factory," Merchant said in an interview with CBC News.

Merchant alleges in the statement of claim that reports of unintended acceleration rose dramatically after 2002, which is when Toyota began using electronic throttles in some models, including the Matrix and the Vibe.

Toyota Canada has not responded to a request by CBC News for an interview.

The allegations go on to say that several automakers that also use electronic throttles have provided an electronic or mechanical override to make it easier for drivers to stop their car even if there's pressure on the accelerator.

However, Toyota has "failed to provide such fail-safe in the Pontiac Vibe," the suit alleges.

In court papers, Merchant alleges Toyota also "concealed" from government regulators, consumer groups and the media "an entire universe of potentially relevant customer complaints."

"For example, the report from a driver who had experienced a sudden acceleration which lasted for a considerable time would not be seen by the NHTSA [National Highway Traffic Safety Agency] because Toyota did not include it in its response, since it occurred for a 'long duration.'

"Similarly, a driver who reported that he was standing on the brake and could not overcome the open throttle would have had his report excluded from the investigation," says the claim.

Last month, Merchant launched an action against Toyota, alleging some Toyota and Lexus hybrid vehicles have defective braking systems.

In the past, he's also launched proceedings against Honda, alleging defective suspension systems, and against GM, alleging defective transmissions in its Saturn line of vehicles.