Tag Archives: Toyota

Root Cause Analysis - Incident Investigation

Toyota Recalls Millions of Vehicles Because of Fire Risk

By Kim Smiley

On October 11, 2012, Toyota announced a recall of 7.4 million vehicles worldwide due to a potential fire hazard.  This newest recall comes on the heels of the heavily publicized unintended acceleration issue and puts Toyota once again in an unwanted spotlight.

A Cause Map, a visual format for performing a root cause analysis, can be built to help analyze this issue.  The first step in building a Cause Map is to create an Outline that lays out how the issue impacts the overall goals of an organization.  In this example, the safety goal is impacted because of the potential for injuries and car accidents.  The production goal is impacted because of the effort needed to recall millions of vehicles.  The customer service goal is also impacted because of the negative publicity that a recall of this size will generate.  After the impact to the goals is determined, “why” questions are asked to determine what causes contributed to the issue and to create the Cause Map.

Starting with the production goal, we would ask “why” millions of vehicles were being recalled.  This is happening because there is a component that may need to be repaired, the component is in many vehicles and there is a potential for injuries if the component isn’t repaired.  A component needs to be repaired because the power-window switches pose a fire risk.  Some of the power-window switches feel sticky when operated and if some commonly available lubricants are applied it will create a fire hazard because the switch can melt.  There are millions of these power-window switches to repair because they were used across multiple models for several years because using standard parts is usually cheaper.  There is a potential for injuries because a fire starting in the power-window switch while the car is driving would be pretty distracting.

This recall will generate negative publicity because it is a huge recall, the a largest vehicle recall since Ford Motor Co recalled 7.9 million vehicles in 1996, and the timing is a bit unfortunate since it comes shortly after the unintended acceleration issues that resulted in large recalls.  In fact, some of the vehicles being recalled this round are the same vehicles that have had previous recalls, a fact that probably isn’t reassuring to owners.

The good news is that the fix for this problem is relatively simple beyond the innate hassle of taking a vehicle to the dealer.  The recall consists of a technician inspecting, disassembling and applying approved fluorine grease to the power-window switch, improving the sticky operation and decreasing the likelihood that some handy soul might apply an unapproved lubricant and inadvertently melt the part.

To view a high level Cause Map of this issue, click on “Download PDF” above.

Root Cause Analysis - Incident Investigation

Possible Toyota Prius Recall

By Kim Smiley

A new potential safety issue has developed and Toyota may recall the newest model of the gas electric hybrid Prius that has been sold since last May.  The National Highway Traffic Safety Administration has received 124 reports from consumers claiming that the brakes don’t engage immediately at times.  Toyota has stated that the company has received 180 reports of braking problems in Japan and the United States. The reports include 4 incidents that resulted in accidents with 2 people receiving minor injuries.

Even a slight delay in the response of car braking systems can be very dangerous because cars can travel nearly 100 feet in one second at highway speeds.

No official details are known yet on what is causing the delay in brake engagement.  In one article, a power train expert speculated that it was a software glitch caused when the hybrid switched between using the electric motor and the internal combustion engine.  In the Prius design, the same motor that is powering the car, powers the brakes.  When the hybrid is switching between motors, there might be a momentarily loss of power to the brakes during the transition.

A preliminary root cause analysis can be started using the available information.  The Cause Map can be expanded and revised as necessary as new information becomes available.  Click on the “Download PDF” button above to view the initial Cause Map.

Toyota has not stated whether a formal recall will be made.  A potential recall would affect 300,000 vehicles worldwide.

This new issue comes on the heels of a major announcement on January 21 where 2.3 million cars were recalled because of sticky gas pedals that can cause sudden acceleration. Additionally, there was a recall issued in September 2009 because there was a potential for floor mats to move out of place and cause the accelerator to stick. (A previous blog addressed this issue.)

Toyota shares dropped 21 percent following the January announcement and any farther safety issues will likely negatively impact consumer confident and stock prices.

Root Cause Analysis - Incident Investigation

Toyota Recall: Problems, Interim Solutions and Permanent Solutions

by Kim Smiley

On September 29, 2009, Toyota/Lexus issued a safety advisory that some 2004-2010 model year vehicles could be prone to a rapid acceleration issue if the floor mat moved out of place and jammed the accelerator pedal. Although the recall is only applicable in the U.S. and Canada because of the type of floor mats used, over 4 million vehicles are affected by the recall.

Although all the solutions to this problem have not yet been implemented, we can look at the issue so far in a Cause Map, or visual root cause analysis. First we define the problem. Here we could consider the problem the recall, or the acceleration problems. We can list all the models and years that are affected by the recall, and that the recall is limited to the U.S. and Canada.

We define the problem with respect to the organization’s goals. There have been at least 5 fatalities addressed by the National Highway Transportation Safety Administration (NHTSA), though some media outlets have reported more. Additionally, the NHTSA has reported 17 accidents (again, some claim more) and has received at least 100 complaints. The fatalities and accidents are impacts to the safety goal. Complaints are impacts to the customer service goal. The recall of more than 4 million cars is an impact to the production/schedule goal, and the replacement of the accelerator pedals and floor mats as a result of the recall is estimated to cost $250 million, which is an impact to the property goal.

Once we’ve completed the outline, we can begin the Cause Map, or the analysis step of the process. The fatalities are caused by vehicle crashes resulting from a loss of control of the vehicle. The loss of control is caused by a sudden surge of acceleration, inability to brake, and sometimes an inability to shut down the engine of the car. Toyota says the sudden bursts of acceleration are caused by entrapment of the accelerator pedal due to interference from floor mats. Toyota refutes the possibility that there may be a malfunction in the electronic control system, saying it’s been ruled out by Toyota research.

The vehicles are unable to brake because the brake is non-functional when the accelerator pedal is engaged, as it is in these cases. Additionally, owners whose models are equipped with keyless ignition cannot quickly turn off their ignition. These models require the ignition button to be pressed for 3 seconds to prevent inadvertent engine stops, and the instructions are not posted on the dashboard, so owners who weren’t meticulous about reading (or remembering) instructions from the owners’ manual may not know how to turn off the car while moving at very quick speeds.

When the Cause Map is complete to a sufficient level of detail, it’s time to explore some solutions. In this case, the permanent solutions (which will reduce the risk of these accidents most significantly) to be implemented by Toyota are to reconfigure the accelerator pedal, replace the floor mats, and install a brake override system which will allow the brakes to function even with the accelerator pedal engaged. However, designing and implementing these changes for more than 4 million cars will take some time, so owners of Toyotas require interim solutions. Interim solutions are those that do not sufficiently reduce the risk for long-term applicability but can be used as a stop-gap until permanent solutions are put in place. In this case, Toyota has asked owners to remove floor mats, and has put out guidance that drivers who are in an uncontrolled acceleration situation should shift the engine into neutral, which will disengage the engine and allow the brake to stop the car.

View the high level summary of the investigation by clicking “Download PDF” above.

Learn more about the recall at the NHTSA website.