Has Toyota Solved SUA?

I remain skeptical in the light of Toyota’s latest statements that driver error caused “virtually all” of the unintended acceleration problems that have plagued the carmaker for the past decade.

Per the Wall Street Journal, NHTSA analysis of the affected cars’ “black boxes” found instances in which throttles were open and brakes hadn’t been deployed, suggesting drivers were pressing the gas, not the brake. (NHTSA isn’t commenting.)

The dreaded sudden unintended acceleration is supposed to have caused up to 89 deaths in 71 crashes since 2000.

Admitting in advance that my reasons are somewhat circumstantial, I would counter that Toyota

1. Has failed to provide solid evidence to refute a university researcher’s claim that the electronics wiring could be the cause, and that the car’s software lacked a fault code to point out the defect.

2. Has failed to explain why the rate of accidents attributed to SUA is not similar in competitors’ vehicles.

That said, the shims the carmaker has installed beneath the accelerators, the complaints over SUA appear to have subsided. Perhaps Toyota was correct, after all.

(Full disclosure: My wife drives a Prius.)

Where’s There’s Toyota, There’s Fire

The sudden unintended acceleration problems in Toyota’s vehicles have touched off a firestorm of controversy over the cause(s). Now, a professor of automotive technology at Southern Illinois University has entered the fray, testifying before Congress that the trouble locating the problem’s source could stem from a missing defect code in the affected fleet’s diagnostic computer.

In testimony before a house subcommittee  Tuesday, David W. Gilbert, a Ph.D. with almost 30 years experience in automotive diagnostics and troubleshooting, said his initial investigation has found problems with the “integrity and consistency” of Toyota’s electronic control modules to detect potential throttle malfunctions.

Specifically, Prof. Gilbert disputed the notion that every defect would necessarily have an associated code. The “absence of a stored diagnostic trouble code in the vehicle’s computer is no guarantee that a problem does not exist.”

In fact, using a 2010 Toyota Tundra, Prof. Gilbert discovered electrical circuit faults could indeed be introduced into the electronic throttle control system without setting a diagnostic trouble code. “Without a diagnostic trouble code set, the vehicle computer will not logically enter into a fail-safe mode of operation. … Since the vehicle computer will only react to defective sensor inputs outside of the range of programmed limitations if the circuit is not defective; it must be good.” In other words, because a code did not exist for the sensor to inform the on-board computer of a problem, when a short occurred the computer did not recognize the problem, and therefore it took no steps to mitigate it. And absent the code, no defect was entered into the database for post-incident tracking.

Prof. Gilbert further determined that electronic control module malfunction detection strategies were not sufficient to
identify all types of fundamental APP sensor and/or circuit malfunctions. “Some types of electronic throttle control circuit malfunctions were detectable by the ECM, and some were not,” he testified. “Most importantly, the Toyota detection strategies were unable to identify malfunctions of the APP sensor signal inputs to the ECM.” (Watch this video of Dr Griffin’s test at his university test track.)

Yikes! If Prof. Gilbert is correct, this could explain why Toyota engineers have failed to diagnose the electronics as a potential source of sudden unintended acceleration. As one reliability expert told me, this could be the smoking gun.

We await Toyota’s response to this revelation.