POLL: Did the ECU Update Recall work for you?

Could you clarify the difference between "able to duplicate" versus "experienced":

I won't be getting my upgrade until Saturday and it may take a while before I can retest under similar conditions.

Thanks,
Bob Wilson

 

How about a "Did not experience it before/have not experienced it since" option?

 

You moderators have all the fun.

Tom

 

Here's one of the problems I see with figuring this stuff out:
I've been driving cars with ABS (and non-ABS cars too) since 1991. And still, every time ABS kicks in, it feels funny to me. I think that's because it only comes on in unusual circumstances, and it feels very different from normal braking--i.e., the car is fighting back.
Now, I think that I experienced "the Prius brake problem" twice, at a particular uneven part of our gravel driveway. But could I absolutely prove that? I'm not completely sure that it wasn't just the funny feeling of antilock braking fighting back.

I guess my conclusion will be that this poll may be suggestive, but I'm not at all sure that all of us (including me) will give the accurate answer, no matter how subjectively truthful we try to be. (And, I guess I have to say that this applies to the poll that was up for some time about whether we felt the anomaly).

BTW. I just got the ECU update done today, so my answer now is I have not had time to see if it has fixed the problem I think I have.

And they were good and quick about it, and also changed my "backup beep" to a single beep without charge. (Caldwell Toyota, Conway, Ark.)

 

I just had the AOB recall done, and I really never had an issue with the brakes before. I can tell you the brake pedal now does "feel" different, you can definitly feel the hydraulic brakes engaging sooner at low speed. I'm not sure this is any better, but it is what it is.

Mitch

 

Had SSC-A0B performed today at my Toyota dealer. It took 1-1/2 hours (which I was told about when the appointment was made and they were "swamped" with other customers getting their accelerator pedals recalled). Everything seemed to go well and they weren't too put out with me when I showed them the directions/update files posted here.


I haven't had a chance to take it over the man hole covers at the intersection where I had my one "event" but all I can tell now is that it seems you don't need to push the brake pedal as far down before it responds. I'll post again after I brake in the previous spot of the one occurrence.

2-14-10: Took the car over the same two manhole covers while braking before the intersection of Route 30 & Route 45 where my one "event" occurred; the braking worked fine with minimal "slip/acceleration" after hitting the covers. This is only one test but so far, the update worked. There is a Google picture of where the original event took place in another thread.

2-21-10: Took the car over the same two manhole covers again today while braking before intersection Route 30 & 45 (~ 15-20 MPH and decelerating) where the one "event" occurred; braking AGAIN worked fine with just very minimal slip (similar to our traded 2005 Prius). This is the second time and it still did not demonstrate what I experienced before the software update. I'd now say it did "fix" the brake "issue. (if that's what you want to call it; was really a NON-ISSUE!)

 

Hi everyone - I had the fix done yesterday and I can say that it now prevents the issue I had dealt with at some railroad tracks by my house. I also took the recall opportunity to have them make the reverse beeping go from continuous to one beep only (for free).

 

Hi folks,

I can't vote, yet. I'll have to wait for a drizzle to replicate the brake pause. However, the street by the dog park has grown some impressive potholes including one at least 4-5 inches deep and 7 ft long. So I ran a series of accelerometer measured tests before and after A0B:

• Pre-A0B - the braking incidents showed a 50% decrease in braking force for ~600 milliseconds in each trial. Braking force did not go to zero as it did in my Feb. 5 capture.
• Post-A0B - the braking incidents shows no decrease in braking force after the pot holes.

This data strongly suggests some part of the brake pause is gone BUT I was unable to replicate the complete loss of braking force during the pause. For that I'll need a slippery surface after the bump. The Hunstville police department takes a dim view of such field modificatons and our driveway is too short.

We have time before the poll closes but these are encouraging data:




Bob Wilson

 

I'll have to take your word on this as I cannot figure out how to read these graphs and to me it looks like there was bigger drop out in the one labeled "post A0B." Again, I don't really understand what I'm seeing here; sorry.

 

No problem.

The following chart is labeled "before A0B fix":

You'll notice before the pot hole, the braking deceleration was about 150 counts, 150/1100 ~= 0.14 G. After the pothole, the braking deceleration dropped to 75 to 50 units, 75/1100 ~= 0.068 G to 0.045 G.

The same test protocol over the same pothole "after A0B fix" shows:

You'll notice just before the pothole event, it was 200 counts, 200/1100 ~= 0.18 G. After the pothole event, it also held around 200 counts, ~0.18 G. But this is not the exact same test scenario as the rain slick, Huntsville streets and speed bump. Weather permitting, I'll repeat that test sometime in the next day or so.

Some technical details about the chart:

• small blue circles - these are the X-axis accelerometer values showing front and back acceleration values. A positive value is braking and a negitive value is acceleration. Sampling at 160 per second, they appear to be scattered but when lines connect them the ABS operation is clear. In this case, ABS modulations do not contribute to our understanding.
• small pink boxes - these are the Z-axis, or vertical acceleration values. When they show up, the car is making significant up and down motions.
• black trendline - this averages 16 adjacent X-axis accelerometer values to remove the ABS variations. This is what is used to smooth the braking force.

Now we can use Newton's law:

Force = Mass * Acceleration
​

Since the Mass remains constant, the Force is proportional to the Acceleration. So all it takes is an accelerometer and the iPod Touch and iPhone have one built-in needing only software to record the data.

Bob Wilson

 

Forgive us our ignorance...

What I think I get:
each graph covers a 2 second period.
before A0B, you hit the pothole about .5 seconds into the graphed period, and the brake loss in seen in the solid line, mostly for .2 or .3 seconds

What I do not get:
after A0B, you hit the pothole about .9 second into the graphed period, and it looks like the solid line still shows a drop off...

Obviously, I'm looking at this wrong.

 

I presume the point is that:

Pre-fix: after the bump you have less braking force.

Post-fix: after the bump you have about the same braking force.

The post-fix case had a bigger bump so the loss during the bump was greater. But the idea of the fix is to to make sure that after the hydraulics kick in you don't have to press the brake harder to slow down at pre-bump rate.

 

Within the limits of informal experimentation, I can no longer replicate the brake pause. It was difficult to replicate before the fix so I can't rule out circumstances that might lead to a similar brake pause. But combined with the earlier, pothole tests, I'm reasonably confident the brake pause is gone.

WET STREET, SPEED BUMP BEFORE A0B



WET STREET, SPEED BUMP AFTER A0B



Understand that in testing we can only disprove a hypothesis. Furthermore, intermittent problems often come with a second cause so I would not rule out others having the problem show up. But this result gives me reasonable confidence to call it solved.

Bob Wilson

 

Bob,

As I posted earlier and on another thread, after SSC-A0B I went over the same two manhole covers while braking around 15-20 MPH approaching the intersection for a right turn and post fix there was no feeling of loss of braking ("acceleration") after the slight drop of going over the covers. Nothing as scientific as your method but my impression just the same.

This was only one time and I'll report if I ever feel the same sensation again.