code P3191

Discussion in 'Generation 1 Prius Discussion' started by deadeyedtt, Mar 18, 2010.

  1. deadeyedtt

    deadeyedtt New Member

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    I have a 2003 prius with the code P3191.I want to know whats wrong with my car. I get over 40 mpg and have 135000 miles on it. I have asked a dealer near me and they really couldnt tell me anything. Please help me. Thanks
     
  2. Patrick Wong

    Patrick Wong DIY Enthusiast

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    DTC P3191 means engine no-start. This is a well-known issue with Classic.

    There are a few things that you can do to take care of this problem:

    1. Clean the throttle body interior and throttle plate to remove the black gunk that you'll find within. Make sure the throttle plate rotates freely when the car is IG-OFF and you turn the spring-loaded shaft.

    2. Make sure that the iridium spark plugs are in good condition; note the service interval is 60K miles. While you are at it make sure the engine air filter is not dirty.

    3. Make sure the engine oil viscosity is 5W-30 and the oil level is not above the top dimple on the dipstick.

    4. After taking care of the above, if you still have trouble, then check your engine ECU part number. The latest version has part number 89661-47054. This allows more time for the engine to start before logging the DTC and turning on warning lights. If your ECU is downlevel then you can buy a salvage ECU for ~$300 and that should take care of the problem. Also do a search for TSB EG011-03, for more details.

    Good luck.
     
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  3. Elliot Lee

    Elliot Lee Junior Member

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    Upgrading the ECU to 89661-47054 did not fix it for me. Neither did replacing the MAF sensor.

    P3191 happens for me on start in cold weather or after it has rained. I can reliably work around it by shifting from Park into Neutral while MG1 is still trying to start the engine. This does something to get the engine started properly.

    T-SB-0180-09 is the latest TSB on this issue and does not mention ECU replacement as a solution.
     
  4. ChapmanF

    ChapmanF Senior Member

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    Shifting to neutral removes all load on the engine. It could be that it is just barely starting, i.e., producing enough power to spin itself around, but is tending to stall under even the minimal electrical load being put on it when the car's not in neutral.

    The reasons for a gasoline engine being balky to start are pretty much the same old suspects, even if there's a lot of fancy tech around it.
     
  5. RRxing

    RRxing Senior Member

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    The Three Amigos!
     
  6. ChapmanF

    ChapmanF Senior Member

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    And compression, the annoying guy who's always following them around.
     
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