Stalling risk in Toyota Corolla, Matrix vehicles gets more scrutiny

U.S. auto safety regulators have stepped up a probe into the risk that up to 1.2 million Toyota Corolla and Matrix vehicles could stall because of defective electronic engine control units.

Regulators began an engineering analysis Wednesday into the reports of stalling in Corolla and Matrix cars from the 2005, 2006 and 2007 model years.

The National Highway Traffic Safety Administration had received 26 complaints of vehicles stalling when it opened a preliminary evaluation at the end of November 2009. It reported 163 complaints when it opened the engineering analysis.

The investigation, which said Toyota Motor Corp. had found two potential causes of production defects in the engine control units, comes in a period of intense scrutiny for the company, which has recalled more than 11 million vehicles in the last year.

“The engine can stall at any speed without warning and not restart,” NHTSA said in a report on its website.

A Toyota representative could not be reached immediately for comment. In a March 2 letter to NHTSA, Chris Santucci, Toyota’s North American regulatory affairs manager, had said the company did not believe the alleged defect “creates an unreasonable risk to motor vehicle safety.”