Toyota Runaway: How it Might Happen

Here’s a link to the actual document:
http://energycommerce.house.gov/Press_111/20100223/Gilbert.Testimony.pdf
Some from Toyota claimed that Dr. Gilbert’s test doesn’t match the real world. Looks to me that his analysis and simulation match the real world very well.

The scenario is very plausible. Basically, there are two signal wires from the pedal to the computer, and at least one power wire to the pedal.
Dr Gilbert found that if the two signal wires short together, the computer doesn’t notice. The car may not behave quite right, but the driver likely wouldn’t notice.
The wires don’t have to be perfectly shorted: some resistance in between them gives the same result.
Now, while those wires are partially connected together, if somehow the power lead to the pedal briefly touches one of them, the computer snaps the throttle wide open. That means, a problem with the wiring harness could cause the motor to run at full throttle.
The computer does not set any error codes when this happens.
Shazam: A wiring harness problem can send the car into runaway with no trouble code set. And, since wiring problems are often intermittent, it can “fix itself” for some unknown period of time.

Dr. Gilbert seems to have very good technical credentials. They are summarized in the PDF linked above.

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One Response to Toyota Runaway: How it Might Happen

  1. jmaechtlen says:

    I am having second thoughts on this – if the wiring harness is damaged enough to partially connect those three wires together, a runaway could occur. But, there are six wires in that harness, I believe. If harnesses are getting damaged, you wouldn’t expect them to all be damaged in one particular manner. The harnesses were damaged in any other manner, the computers would set an error code, and we would see quite a few Toyotas getting wiring harnesses replaced, more than twice as many as we’ve had complaints of acceleration problems.

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