Prof. Dave Gilbert’s Findings on SSUA

ABC News yesterday (Feb 22, 2010) had a video segment on findings made by Prof. Dave Gilbert of the University of Southern Illinois regarding SSUA (Sudden and Sustained Unintended Acceleration) on Toyota vehicles.

Two findings of Prof. Gilbert stand out:

  1. It is indeed possible to force a Toyota vehicle with ETCS-I into sudden and sustained unintended acceleration.    No fail-safe mechanism kicks in.  Recall that there is no brake override (Toyota has promised an update on recent-year models but not earlier-year models), and the driver has to switch to neutral to bring the vehicle to a safe stop.
  2. When the vehicle does go into SSUA, no corresponding diagnostic code is registered in the vehicle.  So, if this happens to a driver and they take it to the mechanic, there will be no trace of the event happening.  Then, it’s your word against the diagnostics!

Both these findings offer very useful insights for those studying whether electronics problems are behind SSUA.

Additional thoughts:

  1. Prof. Gilbert manages to put the vehicle into SSUA repeatably by shorting two pins that go into the Engine Control Module of ETCS-I (Electronic Throttle Control System with Intelligence).    Prof. Gilbert points out that moisture, corrosion and wear can cause such a short to happen.   SSUA has been known to happen even in 2010 Toyota models (for example, there are 18 complaints in the vehicle speed control category of the NHTSA database for the 2010 Toyota Camry).   It would seem unlikely that such new cars have already undergone dramatic wear and corrosion to cause a short.
  2. Toyota’s description of the ETCS-I mechanisms point out the following.  For example, a diagnostic error code is registered only when one of the acceleration pedal position sensors (or the throttle position sensors, both of which have redundant sensors) fails AND one of the redundant ECUs (computers) fails.  If only one fails, no diagnostic code is recorded.  So, it is known that only subsets of conditions are recorded as diagnostic error codes.

What Prof. Gilbert has found is that even a (dramatic) occurrence of SSUA goes unrecorded.  Toyota could perhaps argue that continued acceleration at high speed could be an intended action on the part of the driver, and therefore it should indeed go unrecorded.   If the driver is trying to override the acceleration though, the situation becomes dramatically different.  So, this matter goes back to the issue of ETCS-I in several Toyota vehicles not having a fail-safe mechanism.


One Response to “Prof. Dave Gilbert’s Findings on SSUA”

  1. Toyota plays (hard)ball « Blog on Automotive Safety Says:

    […] however did not say that this WILL happen or how likely it was for it to happen.  Many including me pointed out the relative impracticality of this scenario.   So, there was absolutely zero news on […]

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