Stuck Throttle?

Yes, that is true for most modern vehicles. Remember the reports of Toyota's laptop and downloading of data after the various Toyota and Lexus run-away incidents...

lincomatic said:

I forgot to mention something interesting the engineer told me. He said the car has a data logger that collects data only when triggered by a DTC. The dealer doesn't have access to the data, only Nissan can get to it. My car had no DTC's, so no data.

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lincomatic said:

I forgot to mention something interesting the engineer told me. He said the car has a data logger that collects data only when triggered by a DTC. The dealer doesn't have access to the data, only Nissan can get to it. My car had no DTC's, so no data.

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What's a DTC?

bradleygibson said:

What's a DTC?

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Diagnostic Trouble Code.

The Nissan "Black Box" must be recording data all the time, in a loop (maybe the last 60 seconds?).
Does anybody know how long?
Or, what info is recorded?

Then, if a Trouble Code occurs, the "BB" will have the "recent" history.

For real bugs (unanticipated, so they do not create Trouble Codes), there should be a CTC (Customer Trouble Code) that one can invoke, perhaps by hitting the Start (or Map, or some other) button quickly 5 times, or some such way to indicate a "strange-happening" has just occured.

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When we get a micro-SD card in the SOC-Meter, we hope to be able to have our own "Green Box", at least for the selected CAN-Bus.

With our simple, existing three-CAN (EV, Car, and AV) logging hardware, and a small addition to the CAN-Do software functions, we can easily have our own Brown-Box (several-hour) recorder, or even several-day (or many day) recording to a file, or set of files.

lincomatic said:

bradleygibson said:

What's a DTC?

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Diagnostic Trouble Code.

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Ah, thanks.

That's too bad there aren't any logs to be had...

lincomatic said:

I forgot to mention something interesting the engineer told me. He said the car has a data logger that collects data only when triggered by a DTC. The dealer doesn't have access to the data, only Nissan can get to it. My car had no DTC's, so no data.

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Yup - I think you've traveled way way into lawyer land.

I can't even begin to imagine the conversations about liability and what information to collect and store and when and what to not collect. I guess it comes with the territory when you are a trillion yen company.

Side note (as someone who knows little about OBD II): (all?) cars w/OBD II when they encounter a DTC will record freeze frame data. Over on Priuschat, we've sometimes had people post the freeze frame data they got. See below for some examples I was able to dig up:
http://priuschat.com/forums/generation-1-prius-discussion/96487-new-codes-old-part-deu-4.html#post1372801" onclick="window.open(this.href);return false;
http://priuschat.com/forums/gen-ii-prius-care-maintenance-troubleshooting/82801-she-died-road-anyone-familiar-capital-toyota-in-landover-md-3.html#post1156603" onclick="window.open(this.href);return false;

Perhaps CAN bus experts can chime in an elaborate...

lincomatic said:

I don't want to get people too alarmed, because I wasn't in the car to observe what happened, but my wife had a big scare today. She was accelerating onto the freeway and then had to suddenly slow down due to stopped traffic. She hit the brake, slowed to a crawl, and when she released the pressure on the brake pedal, the car accelerated like the throttle was being depressed. She hit the brake again, slowed almost to a stop, and when she let up, it again lurched forwards. Finally, she pressed the brake pedal very hard. This time, the ABS kicked in, and as it was stopping, the front of the car dived...

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lincomatic said:

She said it was scary ... almost slammed into the car in front of her.

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lincomatic said:

Update...
[...]
Also, I discussed the incident again with my wife, and she said the car wasn't just rolling when she let off the brake, that it lunged forwards.

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One thing that I'm not getting from your otherwise thorough data gathering and reporting is the temporal aspect of this incident. For me, words like "lunges" connotes "very short interval of time", but the account reads as if this happens over a couple of seconds, not in a small fraction of a second.

How long did this "accelerated like the throttle was being depressed" event last? How about the subsequent "lurch forward" event? How about the "pressing brake pedal very hard" and "ABS kicked in" events? If she was at a "crawl", I can't imagine these events lasting more than a fraction of a seconds each?

The reason I am inquiring is because I wonder if you have/she has previously experienced the "oh my God I have no brakes" feeling for a split second when the re-gen braking switches off completely and the hydraulic/mechanical brakes take over? In my LEAF, when on ECO and less than a full charge, when slowing down from speed to a crawling pace, that cut-over is very detectable. It feels like the brake hydraulic just sprang a leak. The brake pedal sinks for a split second and the car lurches forward (there's that word again!) for a split second. The first few times I felt it, I almost needed a change of underwear! (The cut-over is much less pronounced, almost undetectable in 'D'. I think. I'm not sure because it has been a while time since I drive in 'D'....)

Is there any possibility that was what she experienced, twice, as the car crosses back and forth over the cut-over boundary?

lincomatic said:

I know the knee jerk diagnosis is that somehow my wife had her foot on both the accelerator and the brake, [...] Also, the relative positions of the brake & accelerator pedals is such that it's not easy to depress them together unintenionally.

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Yeah, I don't buy that theory even if she was stepping on both at the same time. Given the LEAF's power and its relatively large brakes, I'd be amazed if the motor can overpower the brakes.

Andy,
1) It was a couple of seconds between each time she pressed the brake
2) I was writing from memory when I said she slowed to a crawl the first two times she pressed the brake ... I just asked her again, and she says it was faster than a crawl, but she didn't look at the speedo
3) When this happened, she had already been commuting 30 mi on a daily basis for over a month, so she was familiar with the feeling of the switchover from regen to regular brakes. The feeling was that of getting thrown back in the car, like when you're accelerating, not like the feeling you get when you're just rolling.
4) She drives in D when on the freeway. The only time she uses ECO is when she first sets off from my driveway in the morning, until she gets near the freeway. The rest of the day, she just uses D.

Again, this is her account of it, I wasn't in the car... just relaying her description of the incident.

I always drive in D, except by accident.

The Regen to Mechanical braking seems to be essentially undetectable.

Considering the way the throttle behaves, I'm not really surprised. It may be the computer got confused with the throttle being floored and then immediately released and the brake being applied suddenly. Unfortunately such issues are not always consistently reproducible. What is reproducible every time is if you floor the throttle for at least a couple seconds, as the car speeds up you will find you have to back off almost all the way to prevent it from continuing to accelerate. Then, if you press the pedal again you will find it barely goes any faster. I think this is a side effect of the "auro-ranging" feature. In the case that was described by the OP, maybe the auto-ranging feature didn't have limits set so it was able to consider pedal-off to be equivalent to pedal-on to some degree. Or maybe the event was due to interference of the hall signal - but I would assume that would be one of the first things they'd check. Anyway, I'm no mechanic or engineer - just spouting off.

lincomatic said:

The feeling was that of getting thrown back in the car, like when you're accelerating, [...]

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Great description! The extent of the unintended acceleration is much clearer to me now.

aqn said:

How long did this "accelerated like the throttle was being depressed" event last? How about the subsequent "lurch forward" event? How about the "pressing brake pedal very hard" and "ABS kicked in" events? If she was at a "crawl", I can't imagine these events lasting more than a fraction of a seconds each?

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You know you make a good point here too. I've noticed when I really have to stomp on the brakes, ie when someone cuts me off, the brakes hold themselves on for about another second, probably part of the crash avoidance system. My inclination is to press the throttle harder after said incident and when the brakes finally do release it goes. The ABS may also trigger a similar situation and going over a patch of rough road, maybe even a small bit of sand in the road etc. could potentially cause a similar thing to occur too.

aqn said:

In my LEAF, when on ECO and less than a full charge, when slowing down from speed to a crawling pace, that cut-over is very detectable. It feels like the brake hydraulic just sprang a leak.

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garygid said:

I always drive in D, except by accident.

The Regen to Mechanical braking seems to be essentially undetectable.

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I agree with Gary, and I do drive mostly in D. But I drove a few times in ECO and I have not notice anything. Some times when I start the car I can feel some the brake just had a leak, but only at start. I have never notice it when car was running.

Andy, if it is repeatable I would say you have a problem.

Dan.

aqn said:

In my LEAF, when on ECO and less than a full charge, when slowing down from speed to a crawling pace, that cut-over is very detectable. It feels like the brake hydraulic just sprang a leak.

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garygid said:

I always drive in D, except by accident.
The Regen to Mechanical braking seems to be essentially undetectable.

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camasleaf said:

I agree with Gary, and I do drive mostly in D. But I drove a few times in ECO and I have not notice anything. Some times when I start the car I can feel some the brake just had a leak, but only at start. I have never notice it when car was running.

Andy, if it is repeatable I would say you have a problem.

Dan.

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It's 100% reproducible, and it may well be a real problem, but I'm not yet entirely convinced of that. As such, when others reported similar symptoms, I had not paid much attention; I think there were a few reports/acknowledgements of the issue. I also have not bothered to investigate or report my problem. We have an Austin LEAF gathering coming up; I'll ask around, as well as maybe bumming a drive in a couple of other LEAFs to compare.

If it is repeatable, please give the exact required steps
so that we can try it (and perhaps variations) on our LEAFs.
Thanks.

I have been using D most of the time, but decided to use ECO mode for a week or two to see if I can tell any difference in range after reading the long thread on that topic. As soon as I started using ECO, I noticed the slight release of braking at the transition between regen and friction that Andy described (only at very low speeds). It is 100% repeatable on my car in ECO, but is not noticeable in Drive.

Gerry

garygid said:

If it is repeatable, please give the exact required steps
so that we can try it (and perhaps variations) on our LEAFs.
Thanks.

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I'll take careful note on my commute tonight, but I'm pretty sure a steady and constant "somewhat serious" deceleration coming to a complete stop in ECO will reproduce this behavior (with less than 100% SoC). (If the rate of deceleration scale has "I see a red light and I'm coasting up to it" at one end (zero) and "I didn't see the red light and now I'm slamming on the brakes" at the other (ten), I'd say "somewhat serious" deceleration is about a three or four.)

I think it happens within the last five feet prior to the complete stop. It feels about the same as if you suddenly lift off the brakes a [i[tiny[/i] bit and re-apply it within a fraction of a second.

wow lol i design a differnet alcleration and braking system where if you take it off the petal it would make the car to a safe and complete stop but never made scince it uses dc current to work if i actully made it and went to test i wouldve been fryed but i am thinking of improveing it os i can over ride this pathic problem with an aceleration pedal/braking pedal.Aslo it just gives me a scare when i look at them very much at the leaf's pedal's! :lol:

mechkid said:

wow lol i design a differnet alcleration and braking system where if you take it off the petal it would make the car to a safe and complete stop but never made scince it uses dc current to work if i actully made it and went to test i wouldve been fryed but i am thinking of improveing it os i can over ride this pathic problem with an aceleration pedal/braking pedal.Aslo it just gives me a scare when i look at them very much at the leaf's pedal's! :lol:

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Did your Dad forget to log off of his mynissanleaf.com account again?