The Corvette, as so many obviously know, uses a fly-by-wire (wings *would* be cool) throttle control system. There is no linkage, there is no spring. You step on the gas and the PCM reads the pedal position in much the same way the Joystick works on your PlayStation. The Throttle is controlled by a servo motor. You can see it on either side of the throttle body. One side has a gear driven motor that moves the butterfly (the TAC, Throttle Actuator Control), the other side has a feedback "potentiometer" (the TP, Throttle Position sensor). They share the common pivot shaft for the butterfly. The TAC rotates the throttle plate open or closed, the TP sensor tells the PCM how far the plate has rotated.
For the PCM to go WOT on it's own, one of few issues might be to blame... an intermittent short in the TAC control circuit that causes the motor to be energized even though the PCM isn't asking for more throtle. An intermittent short or open in the TP circuit that causes the PCM to think the throttle needs to be moved farther in order to maintain the correct position. An intermittent short in the Accelerator Pedal Position Sensor. The Throttle Actuator Control Module is flaky.
I took a quick look at the schematic for this section of the Engine Control. The TP Sensor appears to be double-redundant. There are two separate position sensor potentiometers. Similarly, the Accelerator Pedal sensor appears to be triple-redundant. There are three separate potentiometers.
This makes it less likely either of these sensors are failing. While I'm too lazy to look, I wouldn't be surprised if there's a DIC for uncorrelated readings from these sensors. I'd expect you'd have a code if any one of the redunant circuits had failed. But, depending on how GM implemented, it's still possible for these things to be to blame and the computer to not know.
I would start by checking the wiring on the Throttle Body, inspect harness, remove and clean the connectors. If you do that and it happens again, I would replace the TP sensor next. If it happened after that, I'd go with the Accelerator Pedal sensor. And if it still happened after that, I'd replace the TACM.
Or you could take to to a Dealer and let them try and diagnose it.
Either way, the last thing you should do is just hope it won't happen again. In my work, I deal a lot with electronics reliability and the one invariable truth is that failures always increase with time. The fact that it's happened means it will very probably continue to happen, and possibly at an ever increasing rate.
Note: the engine has a rev limiter, stabbing the clutch won't cause any immediate harm. If you have a C5 (which I'm assuming you do) and have the GM Column Lock recall installed, the column lock locking plate has been removed. This means you can turn off the ignition and the steering wheel won't lock. That's probably the preferred choice. And, I wouldn't drive the car with TC disabled.
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Remember the B-2 bomber that crashed on takeoff back in February? If so, you probably didn't read this in your morning newspaper, but the cause was determined to be moisture accumulation. That resulted in inaccurate preflight indications in three of twenty-four sensors, the result being an uncommanded 30-degree pitch-up on takeoff by the FCC (Flight Control Computer). The aircraft also became airborne approximately 1,450 ft. sooner than planned, given the conditions at the time. Subsequently, it led to a stall, whereby the left wing contacted the ground. The rest as they say is history.
Although FBW systems can malfunction, it is not always as a direct result of a failure in the FBW system itself. Other factors can cause problems as was the case with the B-2. Human beings of course are also another factor.
I say that because there were some who were aware of certain conditions which could adversely affect the data being sent to the Air Data Computer and took action to prevent such an occurrence. Unfortunately, there was never a TSO (Technical Service Order) issued detailing the procedure and no other communications or directives were formerly issued either. Hence, only a few maintainers knew of it. Thus, per the USAF incident report...
Quote:
On a previous deployment, maintenance crews found that moisture could foul up sensors unless a special technique was performed. The technique involved heating a pitot tube to burn off moisture before the engine was started. Despite the severity of the problem, USAF investigators found that the technique was not widely communicated among the maintenance crews.
On the day of the crash, a maintainer performed an air data calibration without heating the pitot tube. Because the sensors were coated with moisture, the calibration actually drove transmitted latent errors into the flight control system.
Therefore, theoretically speaking and as RocketSled suggested, something could have occurred which resulted in uncommanded full throttle application. As with the B-2 example above, it may not have had anything to do with the drive-by-wire system itself, as such systems are only as accurate as the data they're being fed.
Any by the way, he did state he took it to a dealer.
The Corvette, as so many obviously know, uses a fly-by-wire (wings *would* be cool) throttle control system. There is no linkage, there is no spring. You step on the gas and the PCM reads the pedal position in much the same way the Joystick works on your PlayStation. The Throttle is controlled by a servo motor. You can see it on either side of the throttle body. One side has a gear driven motor that moves the butterfly (the TAC, Throttle Actuator Control), the other side has a feedback "potentiometer" (the TP, Throttle Position sensor). They share the common pivot shaft for the butterfly. The TAC rotates the throttle plate open or closed, the TP sensor tells the PCM how far the plate has rotated.
For the PCM to go WOT on it's own, one of few issues might be to blame... an intermittent short in the TAC control circuit that causes the motor to be energized even though the PCM isn't asking for more throtle. An intermittent short or open in the TP circuit that causes the PCM to think the throttle needs to be moved farther in order to maintain the correct position. An intermittent short in the Accelerator Pedal Position Sensor. The Throttle Actuator Control Module is flaky.
I took a quick look at the schematic for this section of the Engine Control. The TP Sensor appears to be double-redundant. There are two separate position sensor potentiometers. Similarly, the Accelerator Pedal sensor appears to be triple-redundant. There are three separate potentiometers.
This makes it less likely either of these sensors are failing. While I'm too lazy to look, I wouldn't be surprised if there's a DIC for uncorrelated readings from these sensors. I'd expect you'd have a code if any one of the redunant circuits had failed. But, depending on how GM implemented, it's still possible for these things to be to blame and the computer to not know.
I would start by checking the wiring on the Throttle Body, inspect harness, remove and clean the connectors. If you do that and it happens again, I would replace the TP sensor next. If it happened after that, I'd go with the Accelerator Pedal sensor. And if it still happened after that, I'd replace the TACM.
Or you could take to to a Dealer and let them try and diagnose it.
Either way, the last thing you should do is just hope it won't happen again. In my work, I deal a lot with electronics reliability and the one invariable truth is that failures always increase with time. The fact that it's happened means it will very probably continue to happen, and possibly at an ever increasing rate.
Note: the engine has a rev limiter, stabbing the clutch won't cause any immediate harm. If you have a C5 (which I'm assuming you do) and have the GM Column Lock recall installed, the column lock locking plate has been removed. This means you can turn off the ignition and the steering wheel won't lock. That's probably the preferred choice. And, I wouldn't drive the car with TC disabled.
Remember the B-2 bomber that crashed on takeoff back in February? If so, you probably didn't read this in your morning newspaper, but the cause was determined to be moisture accumulation. That resulted in inaccurate preflight indications in three of twenty-four sensors, the result being an uncommanded 30-degree pitch-up on takeoff by the FCC (Flight Control Computer). The aircraft also became airborne approximately 1,450 ft. sooner than planned, given the conditions at the time. Subsequently, it led to a stall, whereby the left wing contacted the ground. The rest as they say is history.
Although FBW systems can malfunction, it is not always as a direct result of a failure in the FBW system itself. Other factors can cause problems as was the case with the B-2. Human beings of course are also another factor.
I say that because there were some who were aware of certain conditions which could adversely affect the data being sent to the Air Data Computer and took action to prevent such an occurrence. Unfortunately, there was never a TSO (Technical Service Order) issued detailing the procedure and no other communications or directives were formerly issued either. Hence, only a few maintainers knew of it. Thus, per the USAF incident report...
Therefore, theoretically speaking and as RocketSled suggested, something could have occurred which resulted in uncommanded full throttle application. As with the B-2 example above, it may not have had anything to do with the drive-by-wire system itself, as such systems are only as accurate as the data they're being fed.
Any by the way, he did state he took it to a dealer.
Well, the total for damage is over 3k now. They will replace the ECBM and the r/f wheel was gouged (didn't see that) they will try and resurface the wheel. I just hope they get a good color match on the car. It has almost 6 years worth of paint fade sun, rain, etc.
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