The manufacturers will tell you that unintended acceleration is not possible. It is. The technical guys at Astonowners have identified what the root cause is and how it happens.
Makes for interesting and scary reading. In Drive by Wire (DBW) cars the ABS/Brake Control Module is capable of commanding an engine acceleration up to the rev limiter.
In this case, two cars, DB9 with auto box and a V8V manual.

 

I have seen this post on this forum and the other UK based forum.

You aren't putting enough information into the post to make me care, but it does make me wonder what your goal is. I'm glad the Astonowner guys know but probably the most important thing for the rest of us to know is how to put their car in neutral and how to turn their key to shut the engine down... I had a stuck accelerator on an old pickup. It took me more time than I wanted to realize I should jam it into neutral and shut it down, but not really a big deal if you are paying attention to your vehicle.

YMMV.

 

What more info would you like? I guess the objective was to explain that under particular circumstances you can find that the car accelerates on its own. I would hazard a guess that the average owner will have no idea what to do unless they are in a manual car in which case they would instinctively dip the clutch. For the vast majority of Aston owners they have an auto and hitting N is not something they will ever have done.
Looking back in the Forums there are plenty of reports of people hitting stuff because "the car accelerated all by itself".

 

I do put the car into neutral if I am stuck in level road traffic and don't want to keep my foot on the brake pedal.

 

You should find the "plenty of reports on this forum"
Only one in found was Audi 5000....

 

I had looked at car Forums generally, not just 6Speed. Hence I wrote Forums.

 

“In Drive by Wire (DBW) cars the ABS/Brake Control Module is capable of commanding an engine acceleration up to the rev limiter.”

This claim appears highly dubious. I can’t think of any reason to have throttle control in an ABS module, which only operates a hydraulic pump inline with the brake lines. Throttle position is irrelevant to its operation. Further, ABS is only triggered under heavy deceleration,ie., when the driver is standing on the pedal. When the brake pressure is that high it is virtually impossible for a passenger car to accelerate. The car will stop. Car & Driver tried this a couple old decades ago and found that even a supercharged Mustang traveling over 100 mph stopped when the brakes were applied with the throttle wide open.

so, the postulated mechanism not only involves trying an ABS module into the throttle control, but also that the module is operating without the brakes being applied? I’d need to see a pretty detailed technical explanation before I’d accept it.

I’ve been in a few unintended acceleration incidents, but all were in race cars and the mechanisms were specific to the vehicle.

 

We do not have access to the source code on the ECUs or within the Brake Control Module so are not in a position to tell you exactly where tthe commands were being generated but we have data, acquired on AMDS that shows the throttle progressively opening while the throttle pedal input is zero.
This only happened when the wheel speeds and wheel acceleration rates were significantly divergent across the rear hubs.
Was the data being processed in the BCM? ECUs ? We don't know because we cannot see the code but we could clearly see the inputs and the outputs.
Uncommanded acceleration is/was occuring under this specific set of circumstances.

 

Significantly divergent during what driving scenario? Is fuel also added when throttle is opened? There are legitimate reasons for opening throttle without additional fueling. Emissions, deceleration load, etc. To say something is happening without full context is interesting, but doesn't give me much concern.

 

Because we don't have access to the algorithm(s) we cannot say exactly what "Significantly divergent" is in numbers, either in terms of relative wheel speed or relative rates of acceleration but if you look at the graphs below you can make your judgement.



Yes, fuel is definitely being added because the engine revved up to north of 4,000 rpm and that doesn't happen without fuel.
Aston Martin Diagnostic Systeme (AMDS) is an unweildy tool at the best of times but the more PIDs you monitor the slower the sample rate. We did not monitor fuel during these runs because the slower sample rate would likely have missed other things.
This problem occurs under all driving conditions. We saw it at 20mph and at 70mph, driving softly and hard.

I suspect you would be very unlikely to see this in "dry" US states because think this is almost certainly a result of corrosion. You judge whether this is likely to happen to you but if it does you will know to reach for the N.

 

The graphs axes are not marked and thus are difficult to decipher, but appear to consist solely of data from the 4 ABS sensors and the driveshaft sensor. There’s no throttle position data, nor is there any info showing the BCM has control over throttle. Also, the data apparently was generated during a road test so it’s hard to attribute meaning to the speed variations, which can be generated simply by going around a corner.
unintened accel is a thing, as my own experience shows, and it wouldn’t surprise me that a defect/fault in an electronic throttle can lead to it, just like a faulty throttle cable can. Your last post references “corrosion” as a possibility. Your original post seemed to suggest that it was some sort of design defect in the BCM, which caused my reaction.

 

As I posted earlier, the number of PIDs you log in AMDS directly impacts the sample rate. So trying to log all the functions ends up being self defeating.
We logged throttle body position and throttle pedal position and saw uncommanded throttle opening in slower speed testing. This is definitely a commanded situation emanating from the BCM.

 

The reluctor ring in the hub had come free from the inner race of the bearing. When we cleaned up the bearing (after changing it) we could see that the reluctor ring was cracked. The solution is to change the hub.
Knowing what we now know we could, if presented with a car doing this, log the following PIDs on AMDS:

1. Wheel speeds
2. Wheel acceleration
3. Vehicle speed
4. Throttle pedal position
5. Throttle body position
6. Yaw data

The sample rate in AMDS would probably be quite slow but you could clearly show that a loose reluctor ring resulted in uncommanded acceleration

 

if you have to push neutral on an automatic it could take 4-5 sec unless you are really trained for, and during that time at 4000 rpm, i bet you ve driven hundred of meters before you touch the damn button if it works.....at that rpm you will be pushed away in your seat i guess its not easy to touch the neutral then...it wont be touching it but better punching it,

 

Just pull back on both paddles and it will shift to neutral as well.

@rcf Those wheel acceleration plots are insane. RL wheel speed is significantly divergent as you say and negative acceleration shown on the same. It's no wonder the stability system would get confused as that seems fairly implausible to me. Failsafes should kick in by that point, especially since the speed sensor pulse pattern would be interrupted/irregular where the crack developed.