The latest safety issue for Toyota.
Consumer Reports has just labeled the 2010 Lexus GX 460 with a "Don't Buy - Safety Risk" designation. This is the latest is a series of safety related issues for Toyota which is the parent company that manufactures the Lexus models. Previous issues involve unintended acceleration and braking issues on various Toyota models.
The issue at hand is the delayed engagement if the Electronic Stability Control (ESC) system under certain driving conditions. The Consumer Reports test attempts to induce "lift-off oversteer". This test is a normal part of their procedures and all vehicles tested by Consumer Reports are subject to this same test, including the 95 SUV's currently rated.
In simple terms the "lift-off oversteer" test attempts to duplicate the condition which may occur if a driver enters a corner to fast or takes evasive action to avoid an unexpected obstacle. The normal reaction in this type of situation is to quickly lift off the accelerator while turning, this can cause the rear of the vehicle to loose traction. The sliding rear wheels could come around (oversteer) far enough to hit a curb or side off the pavement possibly causing a roll-over accident. The GX 460 slid our farther than any other SUV tested in recent years including the Toyota 4Runner which is built on the same platform.
The problem at hand seems to be how quickly the ESC system reacts to the sliding rear wheels. The Electronic Stability Control is designed to apply the brakes on individual wheels and reduce engine power as necessary to prevent the rear from sliding around. These systems generally work quite well but in the case of the GX 460 the system is slow to react and in the opinion of the Consumer Reports testers the rear end slides to far before the ESC system takes control.
In order to validate the test results Consumer Reports used 4 different drivers and 2 different GX 460 vehicles, all with similar results. Both Lexus and the National Highway Traffic Safety Administration have been notified of the test results. The GX 460 has been on sale for about three months and about 5,000 vehicles have been sold. As of now there have been no accidents reported as a result of this issue.
Toyota engineers are currently working to duplicate the results of the Consumer Reports test and Toyota has issued a "stop sale" on the GX460. If a problem is indeed confirmed the most likely fix for this issue would be a software revision for the ESC control module which would allow the system to engage a little more quickly thus correcting the rear end sliding sooner.
What you can do: If you own a 2010 Lexus GX 460 please take extra care to obey all posted speed limits especially on highway off rams or when traveling twisty roads. Obeying the speed limit and being alert for potential road hazards should help reduce the chances of the "lift-off oversteer: occurring.
Lexus has suggested that they will provide a loner vehicle to owners who would prefer not to drive their GX 460 until a remedy is available.
Customers who have any questions or concerns may contact Lexus Customer Satisfaction at 1-800-255-3987.