348tb..... Slow-Down 1-4 light doesn't come on during startup | FerrariChat
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348tb..... Slow-Down 1-4 light doesn't come on during startup

Discussion in 'Technical Q&A' started by marc556, Jun 16, 2018.

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  1. marc556

    marc556 Formula Junior
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    Jul 15, 2007
    590
    Wiltz (Lux)
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    Marc Foyen
    #1 marc556, Jun 16, 2018
    Dear all,

    One day , one problem.....

    I start with one positive note:
    Yesterday I visited the official technical controle office ( I don't know the right english name).
    I have to visit them every two years.
    Result ? Perfect !

    As you can see on the title, the Slow-down 1-4 light doesn't come on during startup.
    My first idea was the bulb, so I check it .... the bulb is ok.
    So I checked and cleaned all the cluster connexions.... It sounds also good....
    Do you have any idea ?
     
  2. Qavion

    Qavion F1 World Champ
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    Ian Riddell
    #2 Qavion, Jun 16, 2018
    The respective SDECU (slow down ECU) is responsible for putting on the SD light. If you swap over the left and right SDECUs, it will give you a first basic step in faultfinding. If the problem doesn't switch to the other engine bank, perhaps if you post your question in this message thread on the 348/355 forum, you may get an answer regarding what specifically illuminates the SD light during start.

    https://www.ferrarichat.com/forum/threads/348-sdecu-pinout-wiring-diagram

    The circuit for the SD light stretches over multiple wiring diagrams and is rather complex. The wire from the SDECU to the SD light goes through 4 different connectors, so there are multiple chances for corroded contacts (pins and sockets) to cause problems.
     
    ernie likes this.
  3. Qavion

    Qavion F1 World Champ
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    #3 Qavion, Jun 16, 2018
  4. marc556

    marc556 Formula Junior
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    Jul 15, 2007
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    #4 marc556, Jun 17, 2018
    Thank you
     
  5. ernie

    ernie Two Time F1 World Champ
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    Nov 19, 2001
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    The Bad Guy
    #5 ernie, Jun 18, 2018
    With the engine running check the 1/4 ECU to see if it has a silent code (4121) stored for the catalytic converter temperature control unit. If it does, and the engine is running, it means the Motronic ECU is not getting a signal from the cat tcu. If you car doesn't have the button to pull the codes you can make one. Check the 348 DIY thread to find the instructions for making the button.
     
  6. marc556

    marc556 Formula Junior
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    Jul 15, 2007
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    Marc Foyen
    #6 marc556, Jun 19, 2018
    Dear Ernie,
    this button is a very good idea, I don't have it on my car..
    It i
    Is it possible with ECU 2.5 ?
     

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