"... judged the 2010 Lexus GX 460 SUV a Don't Buy: Safety Risk because of a problem we experienced during our standard emergency-handling tests. When pushed to its limits on our track’s handling course, the rear of the GX we bought slid out until the vehicle was almost sideways before the electronic stability control system was able to regain control."
"We believe that in real-world driving, that situation could lead to a rollover accident, which could cause serious injury or death. We are not aware, however, of any such reports."
"All four of our auto engineers who conduct the test experienced the problem in an exercise used to evaluate what’s called lift-off oversteer. In the test, as the vehicle is driven through a turn, the driver quickly lifts his foot off the accelerator pedal to see how the vehicle reacts."
You can look at the Consumer Reports video of its test here.
Consumer Reports says that the GX 460's electronic stability control (ESC) system which is meant to keep a vehicle from sliding out in a turn apparently "doesn't intervene quickly enough to stop the slide, and the rear end swings around too far."
Until the ESC problem is fixed - which looks to be either an upgrade to the ESC's software, or a change in its suspension, tires or shocks according to Toyota - Consumer Report is "urging consumers not to buy the GX 460."
Toyota is now trying to duplicate the problem and come up with a suitable fix. The company says in a Wall Street Journal article that the GX 460 meets or exceeds all US testing requirements and said that Consumers Reports testing is "a little more stringent" than its own.
A potentially bigger issue than the GX 460 for Toyota is a court case winding its way through the Canadian court system. A couple who had an accident involving their 2004 Toyota Lexus ES330 in April 2005 is suing Toyota Canada for more than $1 million for injuries caused by the accident. The couple claim that their Lexus' transmission was defective and caused the car to lurch out of control, according to this story in CBCNews.
Court documents released (look here for about a dozen of them posted by CBCNews) show that Toyota was receiving complaints about the transmission jerking, hesitating or lurching not only from customers but from its Lexus dealers. Some Lexus dealers were claiming that the problems were becoming a "franchise threatening" issue.
Toyota issued software fixes in 2004 to try to correct the problem in the automatic transition, but it found that the fixes did not totally resolve the problem. A hardware solution apparently was discussed, but I could not find out whether it was ever implemented or not.
The reason this Canadian case is important is that Toyota recently got fined by the US government $16.4 million, the maximum available by law, for not disclosing safety defects it had discovered responsible for unintended acceleration in many of its vehicles. In addition, the US government is contemplating another fine against Toyota for a similar reason.
Toyota is calling the problem with its 2004 -2005 Lexus transmissions a "drivability" issue, not a safety issue. Both US and Canadian regulators may not agree, however.
In addition, the software quality/safety issues raised by both the Lexus GX 460 and ES330 don't helpToyota's claim that its auto software is pretty much bullet proof.
As I said, it has been a bad couple of days for Toyota.
Robert N. Charette is a Contributing Editor to IEEE Spectrum and an acknowledged international authority on information technology and systems risk management. A self-described “risk ecologist,” he is interested in the intersections of business, political, technological, and societal risks. Charette is an award-winning author of multiple books and numerous articles on the subjects of risk management, project and program management, innovation, and entrepreneurship. A Life Senior Member of the IEEE, Charette was a recipient of the IEEE Computer Society’s Golden Core Award in 2008.