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Originally Posted by Soleil24
Have you heard about that? . . .
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An interesting article . . .
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Originally Posted by article
Herbert found himself barreling down the road with the cruise control stuck wide open, running approximately 20 miles over the posted speed limit, all the while continuing to accelerate.
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. . . and he still had an SUV 6" from his rear bumper flashing his lights.
The Prius NHW11 (previous model) cruise control schematic shows a switch-resistor network that signals the status to the hybrid vehicle ECU. It takes one "ground" to enable/disable the cruise control. Then it takes the next lower resistance value, "RES/ACC", to put the cruise control in accellerate mode. The key would be seeing "Cruise" indicated on the multi-function display.
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Originally Posted by article
. . . "The dealer informed me that they were able to recreate the safety issue, but they were not able to identify the cause," Herbert said. Three days later, "the Service Manager informed me that they were unable to detect the cause and stated that they would like to ship the vehicle to Cincinnati for further testing," the Prius owner said.
Finally, more than a week after Herbert's Prius was first towed into the Toyota dealership he was told that, "they could not find anything wrong with the vehicle after driving it 300 miles," and that he must return the loaner vehicle the dealer had provided and pick up his Prius.
Herbert was given no information or evidence of any testing or other effort to discover what caused his Prius to run amok.
"The manager indicated that the person who experienced the issue is a porter and was not authorized to make any technical assessments," Herbert said. . . .
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Some form of intermittent short of the wire that connects to the hybrid vehicle ECU's CCS signal (again, NHW11 signal name) might do it. Hitting "Cruise" on the end of the stalk should have shut it down. Sticky "Cruise" button comes to mind too. Now if the 'smart key' technology kept the vehicle from shutting off, this could become a test of the brakes vs THS drive. Also, there should be a 'dead band' between 'ground' and the accelerate value. If not, then an intermittent resistance just at that threshould could be enough to cause the symptom. But pressing the "Cruise" button should have turned it off.
I'll try some experiments on the way into work this morning. While holding the stalk in "ACC" mode, I'll push in and hold the "Cruise" button. If it continues to accelerate, we'll have a reproducable failure mode.
One thing for sure, if it is an intermittent problem, it will return.
Bob Wilson
A Wild Ride in a Prius
