The National Highway Traffic Safety Administration (NHTSA) is opening an investigating into 2009 Volkswagen Jetta TDI cars after receiving seven complaints that the engine stalled while driving. It is estimated that about 38,000 diesel Jetta TDI and Jetta SportWagon TDI models could be affected. The NHTSA thinks the problem may be related to potential fuel system contamination issues.

VW spokesman Kerry Christopher said that Volkswagen takes safety issues very seriously and will fully cooperate with the NHTSA’s investigation.

An intensified investigation into complaints of stalling engines has lead Toyota to recall over one million 2005-2008 Corolla sedans and Matrix wagons. The recall will also include 2005-2008 Pontiac Vibe vehicles. No other Toyota or Lexus vehicles are involved in the recall.

The problem is being blamed on an improperly manufactured engine control unit (ECU) which could lead to the check engine light coming on, hard shifting, the engine not starting or stalling while driving. Toyota has known about this problem since 2005 when it issued a technical service bulletin (TSB). At the time, if a customer came in with any of the above complaints, the ECU was replaced under warranty. If the warranty was up, it was left to the discretion of the dealership whether they would pay for it or not. Now that there has been an official recall the automaker will reimburse customers who paid for the fix.

Toyota and GM will mail owners notices starting in middle September. The ECU will be replaced on all of the recalled vehicles free of charge.

A recall has not been issued yet, but U.S. safety regulators are intensifying an investigation into complaints of stalling engines on Toyota Corollas and Matrix hatchbacks. The preliminary probe begun last November when the NHTSA received complaints for 2006 models, but the problem has been expanded to include almost 1.2 million 2005-2007 Corolla and Matrix cars.

The problem is being blamed on an improper coating on the engine control unit (ECU) circuit boards that lead to cracks in the coating. The NHTSA has received 163 complaints of stalling engines as of last week. It is unclear whether the investigation will lead to a recall.