Feds open investigation into troublesome Hyundai Sonata suspension issue

The National Highway Traffic Safety Administration announced on Friday it is launching an investigation into Hyundai Sonata sedans due to a corrosion problem, which may affect vehicle suspension.

Affected by today's investigation are about 393,000 model year 2006 through 2008 Hyundai Sonata vehicles that may suffer from rear subframe rust, which could lead to rear suspension control arm failure, according to the National Highway Traffic Safety Administration.

The NHTSA has received six complaints so far regarding the rust problems. Three owners complained of control arm failure at highway speeds, while two claimed that the failure occurred during activation of the electronic stability control arm. One owner reported that his dealer found extensive rust, which would cost anywhere from $1,350 to $2,450 to repair. Unfortunately, Hyundai was only willing to cover $500, according to the owner. No accidents or injuries have been reported, according to Hyundai.

Essential to vehicle suspension, the rear control arm connects to the frame by a control arm shaft or a bushing. The arm is generally connected with a ball joint or a pin and bushing. Working in conjunction with a lower control arm, the rear control arm usually houses wearable suspension parts.

Failing rear control arms may exhibit various warning signs that owners should be aware of. Most owners will typically notice a difference in alignment and vehicle handling. A worn control arm may affect the camber angle of the tire. As a result the tire may not hit the road flatly and will begin to show signs of wear. Aside from causing tire wear; compromised rear control arms will affect vehicle steering. Not only will the vehicle pull slightly or aggressively to either side, it will also make steering difficult in general.

Hyundai experienced similar corrosion problems in 2009, which led to four recalls of roughly 608,000 vehicles. The four recalls were as follows:

• 176,000 model year 1999 through 2004 Hyundai Sonatas
• 161,000 model year 2001 through 2003 Hyundai Elantra and Tiburon vehicles
• 188,000 model year 2001 through 2004 Hyundai Sonata, XG300 and XG350 vehicles
• 83,000 model year 2001 through 2003 Hyundai Santa Fe models

If the NHTSA investigation reveals that the corrosion problem poses a serious safety threat it could lead to a recall of certain 2006 through 2008 Sonatas. Hyundai has issued one recall so far in 2013, which concerned 6,100 model year 2012 Veloster vehicles. According to the recall notice, affected Veloster models may be equipped with a faulty panoramic sunroof that was weakened during the assembly process. As a result, the panoramic glass may unexpectedly shatter while the vehicle is in motion.