follow the missing DTCs, Re: Re: Bloomberg news: Regulators Hired by Toyota Helped Halt Acceleration Probes

[David Farber <dave () farber net>]

Begin forwarded message:

From: "Ed Gerck, Ph.D." <egerck () nma com>
Date: February 14, 2010 2:47:55 AM EST
To: dave () farber net
Cc: ip <ip () v2 listbox com>
Subject: follow the missing DTCs, Re: [IP] Re: Bloomberg news: Regulators Hired by Toyota Helped Halt Acceleration 
Probes

[Dave: for IP if you wish]

> > From: "Deborah Alexander" <dsalexan () optonline net>
> >
> > Dave - I am glad that Bloomberg finally picked up the revolving door issue. The
> > case is a damning example of egregious complicity by our federal safety
> > agency between 2004 and 2007.
> > ...

Thanks, Deborah, for the list. I think that it is not enough to investigate current models. One must also look into 
what has been left out of the design itself, specially the missing DTCs (Diagnostic Trouble Codes).

Let me clarify from the software design perspective, where I think this list may have a lot more to say and help.

As car controls make the same move that airplane controls did (fly-by-wire), the question is (as we learned from 
avionics) what's being done to improve diagnosis and add true redundancy to these controls?

For example, Toyota's assertion that if there is no DTC recorded in the car log then there was no software problem is 
not even naive. We all know that most software bugs (and specially the hard-to-find ones) happen when everything works 
fine, when there is nothing that even looks wrong, just that the end result is terribly wrong! For example,  you press 
"Multiply" and the result is always right ... except if one of the numbers has too many decimal digits.

I'd say that the very fact that there's no DTC recorded already shows that something *is* wrong with the design, as 
continued acceleration while breaking should have triggered a DTC and it should have been simple to detect. For 
example, Toyota DTC P1520 (for Stop Lamp Switch Signal Malfunction) detects a malfunction that seems to be far harder 
to detect than "continued acceleration while breaking".

Would it be the case to investigate also Toyota's DTC list and verify what has been left out? DTCs could help, at least 
after the accident, to verify what went wrong. But, what if the thinking is that if there's no DTC then there's no 
fault?

Investigating the DTCs themselves, and the missing DTCs, seems to even more important due to the US regulator stance 
that if there's no DTC then there's no fault. And Toyota reports *zero* DTCs for current incidents.

Best regards,
Ed Gerck
www.gerck.com












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