Sikes accelerator/braking data

I wonder if the last drive cycle was when the car was being moved around at the Toyota dealership? After the SUA episode. Too much speculation for me. I am waiting for NHTSA's report of findings.

 

The last drive cycle is determined by the last time the vehicle went to "READY" mode. Presumably they towed the vehicle into the dealership without taking it out of accessory mode so the counter would still be active for the highway incident. I guess there's no way to prove that definitively, but I think it's fair to say the information is valid...

You have to figure they installed that condition tracking feature just for situations like this.

Andrew

 

Good question. Anybody would be pretty foolish to try to drive a potential missile. It better had to be towed until the formal inspection.

 

250 applications is a lot of moving around the dealership.

Government agencies move slowly. There still isn't a final NHTSA report on the original San Diego Lexus. But it's good to hear that you're going to stop speculating for the next 6 months or so...

 

It took a lot of tries to get it on the rack.

Tom

 

I did so, please see attached. No change.

Hi Andrew,

Pls provide your source for your statement above. Thanks.

 

I just re-read Toyota's quote about the data.

“evidence of numerous, rapidly repeated on-and-off applications of both the accelerator and the brake pedals,”

That would fit with what Andrew said. Toyota says he applied the brake and accelerator simultaneously 250 times. That matches the data that Andrews quote describes.

 

My source is the official Toyota TIS for the 2006 model year Prius under the "Operational History Data" section. I'd rather not post it here for copyright reasons...

The document quoted above appears to be for an earlier year. It sure doesn't look like the one from Toyota's website anyway.

Andrew

 

Actually the mechanic was looking for someone to run over and claim SUA.

 

Can you post a screenshot?

 

This reads like a table of counters rather than a traditional, time-stamped log. Is that how you see it?

BTW, one of the Autoenginuity users reports the most recent update includes the ability to access this data. . . . And I was going to buy another maintenance manual with this paycheck.

Bob Wilson

 

Hi Andrew,

TIS was revised sometime ago, to no longer provide pdf pages from the paper manual. Instead, the appearance of the online pages was changed (making it worse, IMO.)

I think that the provision of one or two pages constitutes "fair use". However I understand that you might disagree.

Regardless of the page appearance, could you at least compare the table that I furnished vs. the table available to you, and let us know if any other conditions were included to be reported?

Hi Bob,

Yes, that also is my understanding after reading the page.

 

After briefly glancing over the values again, it appears that the "accelerator while braking" is the only counter that was added to the operation history information in the 2006 model year.

Andrew

 

It's called gettin' hyphy yo! California is the home of "gas brake dippin"


YouTube - GAS-BREAK-DIP (HYPHY REMIX) BY GATOR SNAPS

Maybe Sikes was gonna try a remake of the famous I-580 shutdown sideshow lol

 

Yes, it's simply an occurence count, and probably has some upper
limit on quantity. I didn't actually realize that "ACCEL AND BRAKE"
had been added later; I was looking at '04 material and then
'10 material. Either way, I would suspect they added that one
just to see how many times someone's force-charging the battery.
Like it's any of their business.
.
Note that the ACCEL AND BRAKE would *not* accumulate the proposed
"on and off gas and brake" behavior, as that's normal one-foot no
matter how often it's performed. However, it may very well
accumulate gas PLUS just enough brake to apply friction but not
incur the override, which I explained the working of in another
thread and is precisely what I most strongly suspect went down.
The problem is that you never know WHEN any of these ECU counters
were triggered; they could still be in there from events a year
old. Unless there's some undocumented timeout. Again, this is
not a "logfile" in the classic sense at all.
.
I still want to know what "engine stays in resonance frequency
band" is; that's got to be the weirdest one of the set.
.
Anyway, to answer the implicit questions, no, I'm not buying this
"he did XXX 250 times" deal until someone details EXACTLY how
and from where it was pulled. If it's misinterpretation of this
same op-hist data, I bet the Toyota techs thought they were
impressing the crap out of all the journos with their high magic
of pulling up stuff like that on their Techstream, but in reality
it's probably completely useless data.
.
_H*

 

The Prius' skid control computer has EXCLUSIVE control over frictional braking, while the main HSD system computer has EXCLUSIVE control over regenerative braking.

When the skid control computer "sees" that braking is required by monitoring the brake light signal it then uses the combination of the brake fluid pressure sensor and the brake pedal stroke sensor to determine the level of braking required.

Then it sends a message to the HSD control computer relaying the information and asking: "of this total how much can you supply?"

If the HSD control computer happens to be in some firmware spin cycle and does not respond to the query then like is happening with the 2010 Prius the braking might not occur in a reasonable timeframe, if all.

In my opinion the HSD computer is somehow stuck in the "set/accel" cruise control mode, endless execution loop and regardless of how much Sikes pressed on the brake pedal the skid control computer would not, did not open the hydraulic brake pressure manifolds at each individual wheel to allow frictional braking.

Luckily the e-brake is mechanically coupled.

 

As much as I might like hard evidence, the counters are not definitive. What I was hoping for was taking the car on an equivalent drive and replicating the result. Give us the protocol:

• We floored the accelerator
• We oscillated the brake between engine cutoff and light braking, "xx and yy levels"
• We used the same route
• We got the same pad and rotor wear w/o rear drum shoe wear

Then add to it a few other lab tests:

• We inspected the brake and power ECUs with 10x to see if there were evidence of a defect
• We examined the quality records for the lot of the skid and power controller and the data was well within normal limits.
• We put the power and skid control ECUs in our lab environmental test fixture including both temperature and shake-and-bake and it performed without error
• We MEGERed the wiring harness and it met "xxxx" specifications

I would love to find a protocol that replicates the brake damage. Then check a previously cleared, diagnostic 'buffer' and show similar counts.

Engineering sometimes has to use less precise means but without making the effort, my mind remains open ... I'm 60% leaning the Sikes incident may be operator abuse but there is not enough to say it definitively. In a civil case, maybe, in a criminal case, no way.

Bob Wilson

 

If Toyota wanted to prove beyond a doubt that sikes was a fake, could they have done more and better testing? I was almost sure that Sikes was a fake until I read the CHP report, going uphill @ 85-90 mph with the brake lights on?

 

I found the "engine stays in resonance frequency band" very intriguing too, but it makes sense. Resonant frequencies are something to avoid in engines/motors/pumps and bridges over the Tacoma Narrows. They cause excessive vibration and premature wear. The military (especially submarines) goes to great lengths to find them and avoid them like the plague.

As far as the 250 brake/accelerator events, I think it's entirely feasible, legitimate, and useful. Toyota knows they are under the world's microscope and I'm sure that they wouldn't let one single tech bozo spout the information without sufficient backup from other Toyota engineers in order to be 100% certain.

You are right, the timing of the events matters greatly. I don't think Toyota would have mentioned it in front of the whole world if there was a good chance it could be information collected over a really long period of time. I'm sure some Toyota engineer asked the same question and made certain that the spokesperson spouted the right information in the press conference. Hopefully the timing of events was also recorded and is divulged by Toyota or NHTSA soon.

Did the 250 events occur over the last 4 hours or the last 22 minutes? If the duration was short and the data is legitimate (which I think it is), then the cycling of brake/accelerator 125+ times is pretty damning evidence and a good indication that Mr. Sikes was up to no good.

 

Yes, I agree that they could have done better testing. I heard this afternoon on a radio talk show that their testing isn't finished, though.

A lot of people are hanging their hat on the fact that the CHP saw brake lights and they saw Mr. Sikes really leaning into the brakes. Anyone can go uphill in a Prius and maintain 90 mph with the brake lights on. I actually did the exact thing in my 2006 Prius a couple days ago on the same exact stretch of highway on my way to Julian. Did it for one minute until I saw with horror that my MPG was only 12!

1. What was the exact slope of the grade? "Uphill" could be 1%, 5%, 10%. Or it could have been a flat portion of a generally uphill stretch. That section of highway has all of the above.

2. For how long did the CHP see brake lights? As far as the police were concerned, they didn't have time on their side, so they were in hurry to "save" this guy and get down to business. They needed to catch up to him very quickly and get alongside to communicate. Thus, it is likely they did see brake lights, but only for a short time (not for miles and miles).

3. Brake lights do not give an indication of the amount of braking. Light braking would give you the same indication as heavy braking. Given the inspection results of the brakes and MGs, it was determined that the brakes were likely pressed lightly for a very long time, or that they were cycled frequently.

4. The CHP say they saw him "laying into the brakes" while alongside. Do they have x-ray vision? Is the door see-through? No, they could only see his upper torso and head. Mr. Sikes could have been laying into the accelerator and lightly pressing the brakes. I can fake what it would look like to "lay into the brakes" without actually pressing hard on them.

5. Yes, at the very end, Mr. Sikes must have laid into the brakes when persuaded by the CHP because his Prius did, in fact, come to a quick stop. :director: