Shift to neutral
Thread Starter
Race Director
Joined: Dec 2007
Posts: 19,030
Likes: 6
From: Maumelle Arkansas
St. Jude Donor '13-'14-'15-'16-'17
Shift to neutral
With the Toyota failures I was just curious what was required to shift my C 6 auto to neutral while driving. Frankly you just don't shift to neutral that often.
Normally when you come to a journeys end you squeeze the shift trigger first, and then shift to Park. This requires you to grip the shift **** and engage the trigger before moving the lever to neutral.
So I checked what was actually required to hit neutral in a hurry. No trigger pull is required, just slap the shifter and it goes to neutral.
I showed this to my wife so she knew she didn't have to even grip the shift lever. Just shove it foreward with any part of your hand. It saves the time required to actually grip the shift **** before moving it foreward.
LJ
Normally when you come to a journeys end you squeeze the shift trigger first, and then shift to Park. This requires you to grip the shift **** and engage the trigger before moving the lever to neutral.
So I checked what was actually required to hit neutral in a hurry. No trigger pull is required, just slap the shifter and it goes to neutral.
I showed this to my wife so she knew she didn't have to even grip the shift lever. Just shove it foreward with any part of your hand. It saves the time required to actually grip the shift **** before moving it foreward.
LJ
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Joined: Aug 2002
Posts: 35,617
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Cruise-In 11 Veteran
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St. Jude Donor '05-'06-'07-'10
Larry, as you noted a shift to neutral requires nothing more than a shove of the shifter to the neutral postion.
It is also worth noting that Corvette (don't know anything about the Toyota system) employs some built in safeguards of it's own in the event of a Throttle Actuator Control problem.
Mechanically, the pedal is spring loaded and is intended to return to the top position as a default.
Also, the throttle actuator assembly is controlled by an electric motor but the blade that opens and closes at the throttle body is spring loaded and the default position in the event of an electrical failure is just slightly open (basically idle power).
The pedal itself has two position sensors, these two sensors are intended to provide redundancy and should be in agreement during normal operation (ie, you lift your foot off the pedal to begin slowing down, both should recognize that the pedal angle is changed. These values are monitored by the ECM.
If a fault or disagreement is detected between the APP (pedal position sensors) the ECM and the throttle body assembly the car will take one of the following actions depending upon the severity of the fault.
Acceleration limiting--The ECM will continue to use the accelerator pedal for throttle control; however, the vehicle acceleration is limited.
Limited throttle mode--The ECM will continue to use the accelerator pedal for throttle control; however, the maximum throttle opening is limited.
Throttle default mode--The ECM will turn off the throttle actuator motor and the throttle will return to the spring loaded default position.
Forced idle mode--The ECM will perform the following actions:
Limit engine speed to idle by positioning the throttle position, or by controlling the fuel and spark if the throttle is turned off.
Ignore the accelerator pedal input.
Engine shutdown mode--The ECM will disable fuel and de-energize the throttle actuator.
So, if you encounter a mechanical fault in the throttle system the car has means of dealing with it electrically as a backup. Inversely, if you encounter an electrical fault in the throttle system the car has means of dealing with it mechanically.
It is also worth noting that Corvette (don't know anything about the Toyota system) employs some built in safeguards of it's own in the event of a Throttle Actuator Control problem.
Mechanically, the pedal is spring loaded and is intended to return to the top position as a default.
Also, the throttle actuator assembly is controlled by an electric motor but the blade that opens and closes at the throttle body is spring loaded and the default position in the event of an electrical failure is just slightly open (basically idle power).
The pedal itself has two position sensors, these two sensors are intended to provide redundancy and should be in agreement during normal operation (ie, you lift your foot off the pedal to begin slowing down, both should recognize that the pedal angle is changed. These values are monitored by the ECM.
If a fault or disagreement is detected between the APP (pedal position sensors) the ECM and the throttle body assembly the car will take one of the following actions depending upon the severity of the fault.
Acceleration limiting--The ECM will continue to use the accelerator pedal for throttle control; however, the vehicle acceleration is limited.
Limited throttle mode--The ECM will continue to use the accelerator pedal for throttle control; however, the maximum throttle opening is limited.
Throttle default mode--The ECM will turn off the throttle actuator motor and the throttle will return to the spring loaded default position.
Forced idle mode--The ECM will perform the following actions:
Limit engine speed to idle by positioning the throttle position, or by controlling the fuel and spark if the throttle is turned off.
Ignore the accelerator pedal input.
Engine shutdown mode--The ECM will disable fuel and de-energize the throttle actuator.
So, if you encounter a mechanical fault in the throttle system the car has means of dealing with it electrically as a backup. Inversely, if you encounter an electrical fault in the throttle system the car has means of dealing with it mechanically.
Thread Starter
Race Director
Joined: Dec 2007
Posts: 19,030
Likes: 6
From: Maumelle Arkansas
St. Jude Donor '13-'14-'15-'16-'17
Larry, as you noted a shift to neutral requires nothing more than a shove of the shifter to the neutral postion.
It is also worth noting that Corvette (don't know anything about the Toyota system) employs some built in safeguards of it's own in the event of a Throttle Actuator Control problem.
Mechanically, the pedal is spring loaded and is intended to return to the top position as a default.
Also, the throttle actuator assembly is controlled by an electric motor but the blade that opens and closes at the throttle body is spring loaded and the default position in the event of an electrical failure is just slightly open (basically idle power).
The pedal itself has two position sensors, these two sensors are intended to provide redundancy and should be in agreement during normal operation (ie, you lift your foot off the pedal to begin slowing down, both should recognize that the pedal angle is changed. These values are monitored by the ECM.
If a fault or disagreement is detected between the APP (pedal position sensors) the ECM and the throttle body assembly the car will take one of the following actions depending upon the severity of the fault.
Acceleration limiting--The ECM will continue to use the accelerator pedal for throttle control; however, the vehicle acceleration is limited.
Limited throttle mode--The ECM will continue to use the accelerator pedal for throttle control; however, the maximum throttle opening is limited.
Throttle default mode--The ECM will turn off the throttle actuator motor and the throttle will return to the spring loaded default position.
Forced idle mode--The ECM will perform the following actions:
Limit engine speed to idle by positioning the throttle position, or by controlling the fuel and spark if the throttle is turned off.
Ignore the accelerator pedal input.
Engine shutdown mode--The ECM will disable fuel and de-energize the throttle actuator.
So, if you encounter a mechanical fault in the throttle system the car has means of dealing with it electrically as a backup. Inversely, if you encounter an electrical fault in the throttle system the car has means of dealing with it mechanically.
It is also worth noting that Corvette (don't know anything about the Toyota system) employs some built in safeguards of it's own in the event of a Throttle Actuator Control problem.
Mechanically, the pedal is spring loaded and is intended to return to the top position as a default.
Also, the throttle actuator assembly is controlled by an electric motor but the blade that opens and closes at the throttle body is spring loaded and the default position in the event of an electrical failure is just slightly open (basically idle power).
The pedal itself has two position sensors, these two sensors are intended to provide redundancy and should be in agreement during normal operation (ie, you lift your foot off the pedal to begin slowing down, both should recognize that the pedal angle is changed. These values are monitored by the ECM.
If a fault or disagreement is detected between the APP (pedal position sensors) the ECM and the throttle body assembly the car will take one of the following actions depending upon the severity of the fault.
Acceleration limiting--The ECM will continue to use the accelerator pedal for throttle control; however, the vehicle acceleration is limited.
Limited throttle mode--The ECM will continue to use the accelerator pedal for throttle control; however, the maximum throttle opening is limited.
Throttle default mode--The ECM will turn off the throttle actuator motor and the throttle will return to the spring loaded default position.
Forced idle mode--The ECM will perform the following actions:
Limit engine speed to idle by positioning the throttle position, or by controlling the fuel and spark if the throttle is turned off.
Ignore the accelerator pedal input.
Engine shutdown mode--The ECM will disable fuel and de-energize the throttle actuator.
So, if you encounter a mechanical fault in the throttle system the car has means of dealing with it electrically as a backup. Inversely, if you encounter an electrical fault in the throttle system the car has means of dealing with it mechanically.
LJ
Team Owner
Joined: Sep 2005
Posts: 20,352
Likes: 568
From: Ventura County, Calif
Thank you for that explanation Paul. I had some idea how it works but didn't know the details.......and I didn't know as much as I thought I knew. 
