355 ECU reset-engine hot or cold?? | FerrariChat
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355 ECU reset-engine hot or cold??

Discussion in '348/355' started by w1how, Jul 24, 2007.

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  1. w1how

    w1how Rookie

    Jan 12, 2006
    22
    Lancashire,UK
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    Marsellus Wallace
    #1 w1how, Jul 24, 2007
    I am aware that when reseting the ecu on a 97 355 that all electrical consumers and ac must be switched off but do you reset the ecu with the engine hot or cold???
     
  2. No Doubt

    No Doubt Seven Time F1 World Champ

    May 21, 2005
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    Mr. Sideways
    #2 No Doubt, Jul 24, 2007
    Does it do any good to reset an M5.2 ecu? Won't your flash memory still have everything stored whether you have power or not?
     
  3. w1how

    w1how Rookie

    Jan 12, 2006
    22
    Lancashire,UK
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    Marsellus Wallace
    #3 w1how, Jul 24, 2007
    Dont think so.The owners manual says to reset the ecu after the battery has been disconnected.
     
  4. No Doubt

    No Doubt Seven Time F1 World Champ

    May 21, 2005
    72,740
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    Mr. Sideways
    #4 No Doubt, Jul 24, 2007
    If you have a '97 355 Challenge with M2.7 ecus, then you would preferably want to reset the ecus when the car was cold so that the learning process for the cold start idle was processed more quickly.

    If you have a '97 355 GTB with M5.2, then I have no idea about your reset process.
     
  5. w1how

    w1how Rookie

    Jan 12, 2006
    22
    Lancashire,UK
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    Marsellus Wallace
    #5 w1how, Jul 24, 2007
    Its a 97 355 GTB with M5.2
     
  6. f355spider

    f355spider F1 World Champ
    Owner Rossa Subscribed

    May 29, 2001
    18,047
    USA
    #6 f355spider, Jul 24, 2007
    Bottom line, I don't believe it matters. If you read the owner's manual and workshop manual (same basic material as far as this ECU reset is concerned) it implies that it should be done while at operating temperature. All it is doing is reseting the idle characteristics (according to the manual), to prevent rough idle or stalling. Not much else. I have performed it a few times over the years, both warm and cold, never saw a difference. After reading posts by ferrari tech Rifledriver, I avoid messing with it now. He says constantly resetting it is not a good thing. He says if you feel a need to disconnect the battery to prevent drain, to buy a battery tender and use it religiously.
     

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