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Discussion Starter · #1 ·
I drive my Prius at 104 MPH, not a wise thing to do, but I need to see the 100 number, then I saw my fuel gage showed full and I had only 6.8 galons of gas in the car. Now I am driving it and I know I only put 6.8 gallon gas in the car and the fuel gage is showing full.
 

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Log a report!

File a bug report with Toyota here. You have to "sign-up" but I always get a human reply to start a dialog with after a week or two.
 

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paul16451 said:
Very interesting...I never would have seen such a bug in the system, and never intend to!
Yah, that's something I want to report (with my name on it). "I was driving nearly double the posted speed limit, and found a glitch in the CPU..." Uh huh...
 

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Well the part that is puzzling is if the software changes behaviour at speed, what other (that may not be as visible) is there lurking in the system? I would wait until there is a new ECU Software release then go to Toyota and demand the reprogram your ECU with the new and improved Software to fix your fuel guage issue.

Also.. I think there is a documented maximum speed in the specs, and it is over 100mph
 

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I don't think it is an ECU problem. As you accelerate, you are probably pushing gas into the fuel level sensing reservoir, making it appear full. Once you level out your speed, in a few minutes it should show your correct fuel level.

The fuel level sensing mechanism is similar to what you'd find on a coffee urn. there is a chamber connected to the main tank with a small hole at the bottom and the top. When the fuel in the tank is steady, the chamber equalizes to that level. Changes to the main tank level would slowly be reflected back to the chamber, so that sloshing around would not cause erratic readings.
 

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DanMan32 said:
I don't think it is an ECU problem. As you accelerate, you are probably pushing gas into the fuel level sensing reservoir, making it appear full. Once you level out your speed, in a few minutes it should show your correct fuel level.

The fuel level sensing mechanism is similar to what you'd find on a coffee urn. there is a chamber connected to the main tank with a small hole at the bottom and the top. When the fuel in the tank is steady, the chamber equalizes to that level. Changes to the main tank level would slowly be reflected back to the chamber, so that sloshing around would not cause erratic readings.
I love a good coffee analogy.
 

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would still be nice though

Would still be nice to be able to get the new SW revs as they come out. Something like PriusUpdate.Toyota.com. Just take your WiFi bluetooth laptop into the Prius, go to PriusUpdate, and use your laptop to proxy the firmware from PriusUpdate to your ECU via WiFi and bluetooth.

Probably a billion ($) reasons why something like that wouldn't fly in the states, but it certainly is tech-possible.
 

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Security is one reason. Yours and Toyota's. Flashing your ECUs is equivalent to flashing your motherboard bios. Most of the time, you have no problem, but woe is you if something should go wrong, like the battery going dead, as you can't be in READY or have ICE charging the HV battery while the HV ECU or the ECM are updated.
 

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Hence the $ in billion. Litigation would be a nightmare as soon as someone hacked your prius, but if security was an issue, they could tie it in with SKS, MD5 checksum the image, incorporate a sessionID with PriusUpdate that is embedded in the FW image sent over BT and add a biometric recon sensor to the MFD (since it's touch sensitive there are a few that come to mind).

I'm sure it will never happen for resons other than technical. Main one is test cycles. If everyone can easily update thier Prius, then there will be more frequent SW revs, which will lead to more introduced bugs, which will lead to more SW revs.....

I think there are even bigger $$ in the billion than any of these though. I don't think that toyota wants anybody to be able to peak at thier FW images. If so, reverse engineering would ensue. No matter what type of encryption they put on it. Last I heard any crypt could be decoded by a good farm of zombie boxes in about 12 months. Plus, why let customers do something, when the dealer can charge for it and make $$.

Still gotta admit, would be kinda cool to flash your prius :D
 

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I was able to update a DVD's software with a CD-ROM disc.

As for the power going out during an update, some devices don't erase the "downloader". Another technique is to load the new software into RAM. Once that is done, it is quite quick to burn it into ROM, thereby keeping the window of danger [when the power might go out] quite small.
 

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Discussion Starter · #14 ·
DanMan32 said:
The fuel level sensing mechanism is similar to what you'd find on a coffee urn.

Dan, I think you are correct and that is the issue with fuel gage. But I saw it full only when I got ot 100 MPH and when I go 80 MPH there is no issue.
 

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Try setting it to km instead of miles. See if it is an overflow problem when it hits 100kph like it does at 100mph. You won't get a speeding ticket for THIS test.
 

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Classic said:
I drive my Prius at 104 MPH, not a wise thing to do, but I need to see the 100 number, then I saw my fuel gage showed full and I had only 6.8 galons of gas in the car. Now I am driving it and I know I only put 6.8 gallon gas in the car and the fuel gage is showing full.
Thank God at least one person here still has his balls!

You made my day! :lol:
 
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