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Posted by David Sherman [24.32.202.83] on Monday, February 01, 2010 at 20:39:41 :
In Reply to: Toyota Recall story posted by Roger in Louisiana [67.142.130.18] on Monday, February 01, 2010 at 19:44:23 :
I think the whole "stuck pedal" theory is a load of baloney. There have been cars with gas pedals and floor mats for a long time. I think the reality is the that "drive by wire" throttle control system is prone to intermittent failures. Apparently other manufacturers have a line in the ECM code to cut the throttle if the driver hits the brakes. Most likely on those cars, if some brief glitch makes the throttle open when it shouldn't the driver instinctively taps the brake, thinks "that was odd", and forgets about it. As I understand it, along with trimming the pedal and mat, Toyota is changing the software. That last part is going to be the real fix. Even then it's not truly a fix, but just what we in the business call a kludge or a hack (technical terms). It will cover up the problem without really fixing it. There is something down in the gory guts of the drive-by-wire system that is getting glitched now and then. It could be a strange confluence of factors in the software, or it could be intermittent components, loose connections/shorts, or actual power-line glitches. I've troubleshot lots of these sorts of things and they can always be figured out given a good lab, good test equipment, and enough time. The key is to first figure out how to force the failure, trying thermal cycling, power supply noise, EMI/RFI, etc, or if you have absolutely no luck with that, instrument the hell out of it, keep a running log of every parameter you can imagine, and set up the equipment to flag the engineer and save all the recently-acquired data as soon as a failure is detected. For what they're going to spend on this recall, they could have $100K worth of data logging equipment in hundreds of cars and let people drive them around until they caught the failure. Instead, they're just going to pretend it's a physically stuck pedal, cover it up by rev-ing the software, and hope that the problem fades from view.
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