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1-4 Slow Down Light...

Discussion in '308/328' started by CliffBeer, Mar 3, 2009.

  1. CliffBeer

    CliffBeer Formula 3

    Apr 3, 2005
    2,192
    Seattle, Washington
    Full Name:
    Cliff
    OK, so here's another thread discussing the 1-4 (or 5-8) Slow Down light on the dash... Specifically, the 1-4 light comes on at start up from cold and just stays on. Based on that, I'm thinking that the ECU has gone bad as the light shouldn't stay on continuously from a cold start. Will try swapping the ECUs and see if the symptoms here replicate for the 5-8 light.

    So here's a question, if the ECU has gone bad, is it a matter of going to the Ferrari dealer and bending over in the parts department? Or, is there a cheaper/better source for a replacement ECU? Any and all help is appreciated - thanks!
     
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  3. spiderseeker

    spiderseeker Formula 3

    Jul 22, 2005
    1,708
    Colorado
    Full Name:
    Steve
    #2 spiderseeker, Mar 3, 2009
    Last edited: Mar 3, 2009
    My experience is with 308's but much more common(and far cheaper about $100) is a bad crank(flywheel) sensor, there are 3 of them, 1 for the tach and one for each bank of cylinders.
    It might just be a dirty connector for the sensor too. I think they should read something like 600 ohms resistance.

    Here is part of a "Birdman" post about it-

    "You can check them. The DC resistance measured with an ohm meter is around 600 ohms. unplug each one from the harness and measure the resistance across the terminals. The problem is that if they are intermittant, sometimes they only flake out when the car is running, not cold with a meter on them. So the meter might say they are fine but they aren't. However, if the meter says a very high resistance (i.e. open circuit) across the terminals, it is definitely shot. With a little troubleshooting you can figure out which one is dead and just replace that one, rather than just replacing them all."
     
  4. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    20,289
    Texas
    Full Name:
    Steve Magnusson
    Yes, this is conclusive evidence that the ECU is not working correctly (no other problem can cause this behavior because things don't/can't heat up instantly).

    Yes, do this to confirm.

    I'm having a vague flashback that one poster mentioned he had built his own replacement ECU, but he didn't share any details. Hopefully, he/she will comment.
     
  5. CliffBeer

    CliffBeer Formula 3

    Apr 3, 2005
    2,192
    Seattle, Washington
    Full Name:
    Cliff
    Thank you Steve...and Steve! I will check out the crank sensors - that's good preventive maintenance anyway. And try switching the ecu's and see if it replicates on the 5-8 light.

    If it does indeed appear that the ECU has gone bad then I'll see if I can get the box open and look for a burn spot on the circuit board or something similarly obvious.

    thanks!
     

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