Defect Investigations
Toyota Defect Investigations by CfIR in 2010 | Publications
CfIR Identified Electronic Vehicle Control Defects Resulting in Recalls in 2013 | Publications
Any crash is related to a combination of roadway factors, vehicle defects, and/or driver errors. The ever-increasing electronic control of vehicles has its benefits and limitations. Modern vehicle drive-by-wire (DBW) systems can have lifesaving outcomes because they can identify and take action (e.g., deploy airbag) based on potentially-dangerous roadway factors and vehicle and/or driver errors. Most of the time, the DBW systems save lives. However, some DBW commands can be fatal (e.g., misinterpreted data causing a crash or preventing airbag deployment causing injury). Since about 1990, all motor vehicles are equipped with Collision Data Recorders (CDR). These devices initially provided impact and status data, as well as deployment commands for occupant protection systems. More recently, vehicles are equipped with DBW systems with electronically-aided driver controls derived from more than 40 control modules interconnected by communication networks. A vast amount of additional data is collected and stored by these control modules. Diagnostic Trouble Codes (DTCs) identify, describe and store events, faults, limitations exceeded and corrective actions made by each control module. The functioning of a control module, access, and storage location codes are defined in its Product Definition Description manual.
CfIR Identified Airbag System Defects Resulting in Recalls in 2014 | Publications
In November 2013, Don Friedman discovered a defective algorithm in advanced airbag vehicles. He filed a defect petition with NHTSA on a defective algorithm that can suppress airbag deployment by erroneously classifying the occupant weight as being too low to deploy the airbag. The defect in the algorithm is fairly simple. This is a design defect in every GM vehicle with the flawed algorithm. In its analysis of airbags failing to deploy in crashes. After 2000, when GM could have introduced advanced airbag vehicles with the flawed algorithm just through 2010, there were 143 frontal impact fatalities in model year 2000 to 2010 Chevrolet Impalas where the airbags failed to deploy; 98 of the fatalities being occupants were lap/shoulder belted. Mr. Friedman found,
"The algorithm for the weight of the passenger used the instantaneous weight to determine whether to inhibit the airbag deployment. [A vehicle] lift and bounce [can] momentarily reduce[d] the weight of the passenger to that of a small adult. Using a weight averaged over a few tens of seconds would have avoided suppressing the airbag and the resulting serious injury and fatality. Since the control module is field reprogrammable a simple recall and modifying a few lines of code can avoid repeat occurrences."