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Please help: Acceleration issue, Red triangle, Engine light

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by MR2006, Feb 24, 2023.

  1. MR2006

    MR2006 New Member

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    Hello, first time poster and complete Prius newbie here. I purchased a 2006 Prius i-Tech (I'm in Australia) from a Toyota dealership just over three months ago, and it came with a 3 month warranty (approx. 170,000km, in great condition). Two months after purchase, the car experienced acceleration issues whilst driving on the highway (it would only accelerate to around 15-20km/hr), the red triangle of death, engine light, VSC and the small exclamation mark all came on (see images). It stayed like that for about 2 days and then magically, once it had been towed to the dealer, the problem went away and no error codes were present. Toyota ran a full scan, were unable to find any issue and could not see any error codes. Note: Roadside service reported the issue as 'lost communication with battery energy - module A' (and they did not clear the codes), however Toyota said this was of no use to them as they use different diagnostic tools to roadside service. After a few days, the car was returned to me and was fine until, one week after the 3 month warranty ended, the same thing happened again. The Toyota dealership have agreed to look at the car for free if I can arrange for towing at my cost, but they have not agreed to pay for the repairs as yet. Wondering if anyone else has experienced this loss of acceleration or has any advice on what the issue could be as Toyota seem to have a hard time replicating it? IMG_2142.JPG IMG_2141.JPG
     
  2. BiomedO1

    BiomedO1 Senior Member

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    Error codes should be present; if those lamps were on for two days; unless someone erased them. That should also show up on the dealership Techstream diagnostic tool - time and date of last reset/erasure. I'm no expert, but it sounds like a loose connection and/or poor ground connection someplace. If the dealership has the cars' complete maintenance history; they can start checking the contact points of the previous work done on the car. Also check the traction battery pack safety cut-off switch. There's been incidences where it wasn't reinstalled properly and broke contact when you hit a bump on the road. Hopefully the dealership will stand behind the cars they sell; because the previous incident clearly wasn't properly resolved. I can already hear the dealership "mouth-piece" saying "you bought a used car, we can't warranty it forever".....

    Good Luck; Hope this helps
     
    #2 BiomedO1, Feb 25, 2023
    Last edited: Feb 25, 2023
  3. ChapmanF

    ChapmanF Senior Member

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    Next time you're in a situation like that, try to get the roadside service person to give you the actual, five-character, code(s), not just the English-language fortune cookie. Nobody at the dealership really wants to search through the repair manual to find a trouble code backwards from the fortune cookie, and especially not from a fortune cookie that came from some other tool and might be worded a little differently.
     
  4. MR2006

    MR2006 New Member

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    Thanks for the reply. I'll definitely ask them to check out all that you mentioned, and yes, they already tried that line about the warranty (even though the issue was reported well within the warranty period!). Thanks again for your reply.
     
  5. MR2006

    MR2006 New Member

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    Good idea. It seems a bit tricky re: codes. The dealership said that it would have been better if no one hooked up their machine to the car in case it cleared the code... but in order to get the car towed roadside services needs to verify that the car isn't working, so they need to hook up their machines (which are generic / non-Toyota machines that don't seem to provide much information other than 'your car is not working'). What I don't understand is that Toyota claims that they can't see any error in the history or evidence that it was cleared. If the error code was cleared, wouldn't it show up as something like 'last cleared on [date]'? Sorry, complete newbie here, trying to understand :)
     
  6. ChapmanF

    ChapmanF Senior Member

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    Yes, the car does track elapsed time and miles driven since a code clear. (The car doesn't actually record the date of the clear, as the ECUs don't give you any way to tell them what day it is. But a scan tool might read the elapsed time from the car, and subtract it from the scan tool's idea of the current date, and show you the result, as being the date the clear was done. That could be bogus if the date on the scan tool isn't set right.)

    Nobody's scan tool should just clear any codes willy-nilly just in showing them.

    Sometimes the human using the scan tool just can't resist pushing that button, though, even when they oughtta know better, and even when you're watching like a hawk. "I'll just help you out here and clear this—" "step away from the car!"
     
  7. MR2006

    MR2006 New Member

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    LOL yes, it could have been a user issue! Thanks for explaining how it all works. Much appreciated!
     
  8. mcelly

    mcelly New Member

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    Did you end up finding an issue? I'm having the exact same error right now.
     
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  9. MR2006

    MR2006 New Member

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    sorry to hear that... i literally just head back from them this morning. They believe it is a problem with the ECU (still figuring out what the ECU does, but perhaps someone else can answer that!).

    They were trying to find a second hand ECU to replace it (which would cost about $150AUD) but the couldn't find one locally. They (finally) agreed to replace it at their cost (when ordered as a new part it is $2,000AUD!)... however they are not 100% sure that is the actual problem. They said the issue could be 'further down the line', so they will test this first and then see what happens. Will keep you posted, but I probably won't find out more until later next week. Hope that helps :)
     
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  10. ChapmanF

    ChapmanF Senior Member

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    Do you have an error code to share? It seems like the OP in this thread was never given the actual error code, just somebody's version of a fortune-cookie paraphrase for it.
     
  11. mr_guy_mann

    mr_guy_mann Senior Member

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    The HV battery ecu ("energy monitor") keeps track of the high voltage battery pack. Battery block voltages, temperatures, amperage- it measures all that and shares it with other ecu's - mainly the Hybrid Control ecu. It also controls the battery fan.

    Posted via the PriusChat mobile app.
     
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  12. MR2006

    MR2006 New Member

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    No, sorry, the Toyota dealership hasn't provided me with the details, just that the ECU is potentially the point of failure (they say they will only know once they replace the ECU if that is actually the issue). If I find out more I'll post it here :)
     
  13. ChapmanF

    ChapmanF Senior Member

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    (y)

    It might even be better to start a new thread. Given that all we really know in this thread is that the original poster had some problem with that car (and wasn't given a code), and you're having some problem with your car (and haven't got a code yet) , there's no way to say if it's "the exact same error" or even closely related. A new thread specific to your situation and your trouble codes might help keep things focused.
     
  14. mr_guy_mann

    mr_guy_mann Senior Member

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    "keep things focused?"
    Bwa-ha-ha. You make good joke.

    You know that 2 or 5 or 10 years from now, someone will revive this thread "Hey, did you ever find the cause, 'because I have the EXACT same problem!"
    Ah, the power of a google search.

    Posted via the PriusChat mobile app.
     
  15. mcelly

    mcelly New Member

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    No error codes yet, but I will ask them specifically about that and update as well! All the “symptoms” are the exact same though, randomly started having slowed/lagging acceleration and the same symbols lit up my dash (triangle of death, check engine, VSC, and little exclamation point). Mostly I’m just a grumpy and broke grad student and I am NOT in the mood to drop 1k+ on whatever this issue is. Please Prius gods, do not let it be the battery, Amen.
     
  16. mr_guy_mann

    mr_guy_mann Senior Member

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  17. mcelly

    mcelly New Member

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    It was my hybrid battery :( It's a 2008 so makes sense.