U.S. safety regulators investigate problems with Jeep Wrangler air bags, Nissan Altima brakes

2008 Wranglers at a Chrysler/Jeep dealership in Englewood, Colo in this file photo.

DETROIT — Auto safety regulators are investigating brake problems with the Nissan Altima and complaints of air bag troubles with the Jeep Wrangler.

The National Highway Traffic Safety Administration said on its website Friday that brake fluid can leak on the Altima midsize car, causing a loss of stopping power.

The investigation, which began on Monday, covers about 440,000 Altimas from the 2007 and 2008 model years. The agency said the brake master cylinder can leak internally, causing a warning light to illuminate. If the light is ignored, the cars could eventually lose braking power.

NHTSA said it has received 20 complaints, none of which resulted in crashes or injuries.

The agency noted that in 2008 and 2009, Nissan recalled about 180,000 Sentra small cars from the 2007 and 2008 model years to fix a defect that caused leaks in the brake master cylinders.

Nissan said in a statement that it is committed to safety and will work with NHTSA in the investigation.

On the Jeep Wrangler, made by Chrysler Group LLC, NHTSA said that the front driver’s air bag can fail to deploy because of a broken electrical circuit. The investigation, also opened Monday, covers about 222,000 vehicles from the 2007 and 2008 model years. The agency has received 29 complaints, but no injuries have been reported.

NHTSA said it contacted 14 of the 29 owners, and six of them had right-hand-drive models typically used by postal carriers.

Chrysler also said it is working with NHTSA on the investigation.

Investigations can end with recalls or findings that there are no defects.

Last week, NHTSA announced that a probe into steering problems with Toyota Corollas found they were not caused by parts failures and no recall was ordered.