355 battery "off" switch/knob reset ECU? | FerrariChat
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355 battery "off" switch/knob reset ECU?

Discussion in '348/355' started by Yassa, Apr 7, 2012.

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  1. Yassa

    Yassa Formula 3
    Silver Subscribed

    May 23, 2011
    1,266
    London
    Full Name:
    Dr Yassa Hughes
    #1 Yassa, Apr 7, 2012
    Last edited: Apr 7, 2012
    Hi guys, just curious if the the battery "off" knob (on the passenger side under the hood) resets the ECU or is a battery disconnect necessary on a 2.7 1995 355?

    I've read somewhere that you need to leave the battery or knob in off position overnight for a ECU reset, but I don't see why that would be...Please correct if I'm wrong but I don't get why it would take 12 hrs to reset the ECU with no current attached.
     
  2. 355rockit

    355rockit Formula Junior

    Dec 1, 2010
    893
    San Marcos, CA
    Full Name:
    Vas
    #2 355rockit, Apr 7, 2012
    The battery disconect switch will allow you to do a reset. On the F355 w/ 2.7 it clears some of the gremlins if done periodlically (given no more serious issue is rearing it's ugly head). Turn it off for ~10 min (others may have differing opinions) and back on. You'll have to do the relearn process which is outlined in your manual. It is basically to turn off all interior accessory electronics, turn on the car and let idle for 15 minutes. Do a mellow drive and turn on the accessories. Shut-off the car and then start again and do a little more aggressive drive.
     
  3. saw1998

    saw1998 F1 Veteran

    Jun 8, 2008
    8,237
    San Antonio, Texas
    Full Name:
    Scott
    #3 saw1998, Apr 7, 2012
    To perform a PROPER re-learn on the ECU of both the 2.7 and 5.2 F355 models you need to turn on the car's headlight switch for several hours (overnight is better) after turning off the battery disconnect switch. There are numerous capacitors in the ECU which must be fully discharged before the re-learn, and this is the best method to do so. As previously mentioned, ALL electrical components must be turned off before the re-learn and the accelerator pedal left untouched (at idle).
     

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