Probe of 2 Toyota models boosted

WASHINGTON - The National Highway Traffic Safety Administration has stepped up its investigation into complaints of stalled engines on Toyota Corolla sedans and Matrix hatchbacks but stopped short of a recall.

The agency is looking at two possible causes behind the stalling: Improper coating on circuit boards and a crack in the surface of a glass coating. Both could have happened during production of the cars.

The new investigation, called an engineering analysis, covers 1.8 million Corolla and Matrix cars from model years 2005 to 2007. It is a more in-depth investigation of the vehicles than the preliminary one that the agency began in December. That covered vehicles from the 2006 model year only.

The safety agency said that as of last week it had received 163 complaints of stalling engines in the cars.

Monika Saito, a Toyota Motor Corp. spokesman in Tokyo, confirmed the investigation. She said Toyota was cooperating fully but declined to give details.

The engineering analysis will determine if there is a safety defect that needs to be fixed. Toyota is trying to patch up its reputation since the recall of some 10 million cars and trucks since October, 2009, over safety problems, including brake glitches, defective gas pedals, and floor mats that trap accelerators.