Toyota Sudden Acceleration Information:
This report by Christopher Gayner, president of Expert Reconstruction Company, provides current news as well as historical and technical background information pertaining to the Toyota/Lexus sudden acceleration syndrome. For questions, comments, or to request a list of source references, please contact Mr. Gayner directly at 888-687-1334 or send an email to info@expertreconstruction.com .
In light of all the sudden unintended acceleration (SUA) claims and related recalls involving Toyota and Lexus vehicles, there is an abundance of published literature available on the subject matter and a large amount of media attention has been focused on the subject in the last several months. However, the allegations of SUA problems have actually been emerging for nearly a decade. Consumer complaints filed with the NHTSA (National Highway Traffic Safety Administration) alleging sudden unintended acceleration began to show up with a notable increasing frequency in the early 2000’s related to the 2002-2003 model year Toyota Camry and Lexus ES 300 vehicles, coincident with the introduction of Toyota’s Electronic Throttle Control (ETC) system. Several NHTSA defect investigations regarding these earlier Toyota SUA issues never resulted in any corrective actions; perhaps in large part due to limited resources and funding cuts at the federal traffic safety agency.
Subsequently, Toyota has been plagued with unintended acceleration claims from a wide variety of models and model years. The latest reports from NHTSA indicate that there have been over 6000 complaints submitted to NHTSA since 2000 regarding Toyota unintended acceleration. To date, several recalls have been initiated (primarily from the 2005-2010 model years) involving approximately 8 million Toyota and Lexus vehicles worldwide and more than 89 deaths have been attributed to unintended acceleration accidents involving Toyota and Lexus vehicles. These statistics are from the end of May 2010 and are up dramatically just in the last several months.
There have been essentially four distinct causative factors or types of defects identified (or that are under scrutiny) in the Toyota SUA incidents: driver’s floor mat interference with the accelerator pedal, “sticky” accelerator pedals, ETC electronic malfunctions, and driver error.
The accelerator pedals in question are the overhead pivot mount type such that the pedal is spring-hinged from above and the pedal hangs down. When the pedal is depressed, electrical signals are generated via rotational (Hall Effect) sensors at the hinge point. The electric signals (voltages) are processed by the engine control module (ECM) which then sends electric current to a motor that controls the position of the throttle plate and ultimately the engine speed. Hence, unlike mechanical systems of pedal-cable-throttle control found in older cars, the ETC system has both mechanical and electronic elements whose overall proper function is dependent on an accurate sequence of electric signal generation, signal micro-processing, and subsequent instructional signal delivery to the throttle (all without internal or external interference or malfunction).
Some pedals may become stuck in an open throttle position due to friction at the hinging mechanism. Other pedals may become lodged by the driver’s floor mat if the floor mat is not adequately secured to the floor. These two phenomenons are the subject of the recent Toyota SUA recalls but combined only account for a fraction of the total complaints and investigations regarding Toyota SUA incidents. The Toyota vehicle with the highest number of fatal SUA crashes (2002-2006 Toyota Camry, based on February 2010 data) is one of the Toyotas that is not subject to a recall based on floor mat interference or a sticky acceleration pedal.
There is currently much debate and controversy surrounding the whole issue of potential electronic malfunctions in the earlier model years of Toyota/Lexus vehicles not yet subjected to recalls. Toyota denies that there are any electronic abnormalities or defects in their ETC system and they have gone to great lengths, including a massive multi-media public relations campaign, to dispel such suspicions and beliefs.
Toyota has been under pressure and on the defensive from Congress and safety advocate organizations for hiring the supposedly “independent” consulting firm Exponent (formerly Failure Analysis Associates) to investigate potential electronic problems with their ETC systems. Exponent issued a 56 page report titled “Testing and Analysis of Toyota and Lexus Vehicles and Components Related to Unintended Acceleration”, dated February 2010. The report concluded that Exponent was not able to identify or replicate any electrical defects or malfunctions in the ETC system after a variety of tests were conducted on several Toyota vehicle models and model years. In addition to potential bias, critics contend that the Exponent tests were not necessarily comprehensive and therefore not conclusive.
NHTSA has recently requisitioned NASA and The National Academy of Sciences to also investigate the potential for electronic malfunctions in the Toyota ETC system. Several possible failure modes are expected to be investigated in the near future including computer/software glitches, signal processing, electro-magnetic interference or EMI (e.g. cell phone, radio or microwave interference), and combinations of potential short and/or open circuit behaviors. It has been a known practice for some time that certain electronic gadgets must be shut down during take-off, landing, and even in flight for commercial airlines, presumably due to the potential for adverse EMI effects on the aircraft.
Dr. David Gilbert of Southern Illinois University claims to have induced an SUA event in a Toyota Avalon by adding a 200 ohm resistance into the accelerator sensing and control loop. The demonstration was aired by ABC news and a video clip of the “test” is available online. Toyota promptly refuted the validity of the Gilbert demonstration and Exponent published another report that essentially accuses Dr. Gilbert of rigging his test to artificially create engine revving.
A tremendous amount of resources, brainpower and money are being poured into the whole Toyota sudden unintended acceleration debacle from all angles. There is also a lot of contradictory technical information and opinions being published that require care and diligence to sort through. One thing that appears certain is that there are a statistically significant number of abnormal acceleration phenomena being reported (if not occurring) in Toyota and Lexus vehicles that are yet to be fully and adequately explained. With all the opposing views and corresponding technical gray area there is clearly a high value to credible first hand accounts of a sudden acceleration event backed up with the corresponding physical evidence that manifested as a consequence (such as vehicle/scene damage or supporting event data recorder evidence). In other words strong testimonial evidence from a firsthand witness and a resulting crash in an environment and situation that would otherwise be highly unlikely.
