Design News: Toyota Problem “Unforeseeable”?
Design News, January 28, 2010: ”Toyota’s sticking gas pedal was an almost-unforeseeable problem, experts say, and the best course of action now is for engineers to ensure that drivers can handle the failure if it happens again.”
Q. I would like to hear how the Reliability Engineering community feels about this. Was it unforeseeable? How can we “ensure that drivers can handle the failure” if the failure is unforeseeable?
Other manufacturers using throttle-by-wire added software that uses a signal from the brake pedal to override the signal from the gas pedal. Apparently someone foresaw the problem.
Q. As more and more of the functions of the driver are gradually taken over by computerized equipment, with the long term goal of eliminating the driver’s participation entirely, how do we assure the “passengers” that all is well? How do we perform Reliability testing holistically?
And finally, though it is not technically related, is the public ready to surrender complete control?
http://www.designnews.com/article/print/446480-Toyota_s_Problem_Was_Unforseeable.php
http://www.nytimes.com/2010/02/08/08webtoyota.html
http://www.washingtonpost.com/wp-dyn/content/article/2010/02/02/AR201002020316
San Jose Mercury News, Sunday, February 14, 2010 Page A1, “Auto electronic controls drawing scrutiny”
Edward. Great article. Look for a follow-on to this article in the latest Reliability Newsletter by Ops A La Carte due to be out next week.
Business as usual…
1. When Toyota had problems with their 5. l V-8 engine, I sent a letter to their spokesman in Torrance. I offered to use reliability statistics to help identify the defective lots and the customers who had engines with the defective parts. No reply.
2. On national TV news, the president of CFX, the company that made the accelerator pedal assemblies for Toyota said, “The product met Toyota’s specifications.” Jim Bagley, president of Applied Materials and Lam RC learned that wasn’t good enough, http://www.asq-silicon-valley.org/component/option,com_docman/task,doc_download/gid,84 (first page).
Business in the future…
Make nonparametric estimates of field reliabilility for all service parts that have appreciable demand. Use those estimates to forecast upper confidence limits on future repairs. If observed future repairs (or parts sales in the aftermarket for out-of-warranty parts) exceed the upper confidence limit, investigate. Http://www.reyrey.com collects ages and mileages of repairs by VIN and part number for in-warranty vehicles, at great, expense, effort, and perhaps with some errors. The automotive aftermarket knows part sales by part number and store. Catalogs tell which parts go into whech vehicles. R. L. Polk and others sell vehicle registrations by zip code, year, make, model, and engine.
Been there, done that, but the company I did it for doesn’t do it any more (http://www.activant.com).
The Toyota situation is also unclear from the standpoint of their apparent policy of not wanting to issue “service bulletins” to their dealerships, or at least not issuing them for public consumption. I experienced a very scary problem with my 2000 Camry back in 2006 where the EBS brakes started to come on in a pseudo-random fashion at low speeds with moderate braking… and all the dashboard lights would flash like crazy. I drove carefully in 2nd gear, using parking brake to the local dealer. Interesting that the problem was “quickly identified” and fixed inside of 2 hours. The technician indicated that the cable harness going to lights on the trunk lid developed a broken wire (ground wire?). Had this been a Ford or Chevrolet scenario… would this have been a no-charge fix associated with a recall?
After working 29 years for the Big 3, I believe a problem of this magnitude has been a ticking timebomb. The business pressure to reduce program cost and timing while increasing the complexity of vehicles has spread the design engineers thin. Thank God it wasn’t us.
Although we can not ever completely anticipate all possible failures, a structured program of Fault Tree Analysis for concievable vehicle failures and system DFMEAs will go a long way to surface potential weaknesses while still in the early design stage, when engineer’s can make corrections or add redundancy inexpensively.