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Poor performance issues, no codes

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by MarkySparky, Jul 3, 2023.

  1. MarkySparky

    MarkySparky Junior Member

    Joined:
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    Vehicle:
    2007 Prius
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    N/A
    My wife's 2007 Prius seems to be having issues lately. The car seems kind of underpowered, and last few tanks of fuel have been low 30mpg's (was 40-42mpg until recently), and smells gassy for a few minutes on startup. No trouble codes either on Dr Prius, nor on Techstream. <EDIT: C1256 brake actuator and B1421 air conditioning solar sensor(factory bug) > (Though not sure what those two codes would have anything to do with this current issue.) But the traction battery is running hot, around 130 or so, and car is struggling to get to 70mph for even a minute or two. Ambient temperature today was about 90F. A few months ago I overhauled the traction battery, replacing a couple weaker cells with good used ones that I individually refurbed recently. Looking at TS and Dr Prius, the numbers all looked pretty good, except for the 130F temperatures. The cat was replaced about a year ago with a reputable one from Amazon, which so far seems to be keeping the O2 sensors happy. I guess tomorrow I may pull the plugs and inspect, maybe do a compression test, and clean the throttle body. Did an oil change a couple weeks ago. I'll check the air filter as well. Someone suggested checking for vacuum leaks, though I would have thought that would have triggered a trouble code. I'm a fairly experienced mechanic, but most of my training was a long time ago, back in the days of carburetors and points ignition. I do have some experience with fuel injection and engine computers, but the Prius seems a whole different level of complicated! I do have the full factory service manual pdf, but so far haven't found any smoking guns. Suggestions would be welcome!
     
    #1 MarkySparky, Jul 3, 2023
    Last edited: Jul 3, 2023
  2. TMR-JWAP

    TMR-JWAP Senior Member

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    Vehicle:
    2007 Prius
    Model:
    Touring
    The car will reduce maximum discharge and charge rates for the battery if it's seeing unusual temperatures. You may want to verify the cooling fan is operating properly and the ductwork has been installed properly.

    There are also two black plastic pieces that are installed on the ecu end of the battery, one on the top and one on the bottom of the module pack, that direct airflow, the top one forces air flow to pass between the modules instead of escaping out the end. If these are not installed, it will cause temperature control problems.
     
  3. Tombukt2

    Tombukt2 Senior Member

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    Vehicle:
    2009 Prius
    Model:
    Base
    That's wild I've got the same converter installed on the same car more than likely I can't get past the PO420 I've just left it for 3 years Said to hell with it I have the same aftermarket catalytic converter from the big maker on eBay and I think they sell on Amazon they're a big outfit with big advertising and they sell to the industry they don't even offer a Gen 3 cat only the two. And I believe this car had that code before the cat was replaced The sensors have been dealt with denso all of that. But the code persists but it affects no gas mileage nothing so I just leave it
     
  4. mr_guy_mann

    mr_guy_mann Senior Member

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    Vehicle:
    2006 Prius
    Model:
    Four
    I would get the car "hot" then drive it while monitoring amps with Dr Prius. On my 2006, I normally see state of charge around 65%, and up to 160A on full throttle accel from a stop. If the SOC is high but amps are low, then the system is limiting for some reason (possibly high temps).

    Temperatures are in the mid 120's on a warm day- don't even notice the fan when it's on speed 1 or 2.

    Posted via the PriusChat mobile app.