328 Slowdown Light Help | FerrariChat
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328 Slowdown Light Help

Discussion in '308/328' started by surfdwn, May 12, 2023.

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  1. surfdwn

    surfdwn Karting

    Sep 28, 2005
    140
    Freeport, Fl
    #1 surfdwn, May 12, 2023
    The Slowdown Light on my 328 had come on the last two times that I drove the car. It happened after 15-20 minutes of driving. After sitting, the light was out. The car was running great, but I was worried about what was causing the issue.

    I left the car sitting for a few weeks before I got a chance to look into it. When I started the car up today, the light came on immediately and stayed on. I know the system goes through a "self test" when the ignition is first turned on, and until today, this part worked.

    I opened the trunk up and pulled out the plate with the ECU and the light controller on it. My plan is to clean all the contacts and try it again.

    I have read many of the posts about the Slowdown Light, but did not find any where the light was on all of the time.

    Any suggestions? If the contact cleaning fails, what next?
     
  2. Dave Bertrand

    Dave Bertrand Formula Junior
    Rossa Subscribed

    Dec 24, 2005
    824
    Castle Rock, CO
    #2 Dave Bertrand, May 12, 2023
    My slowdown light module failed last year. It resulted in the light coming on usually 10-20 minutes into every drive I took. I figured it was a problem with the module itself rather than an overheating cat, so I replaced it with a new module. No problems since. It seems like a common problem as these cars have gotten older.
     
  3. mike996

    mike996 F1 Veteran

    Jun 14, 2008
    6,876
    Full Name:
    Mike 996
    #3 mike996, May 12, 2023
    Yeah -it's a common issue. My 328's slow down began randomly coming on/going off with no change in engine load. It then quit totally, not doing the "check" when the ignition was turned on. This was back in '08. Obviously the modules are now available; back then they weren't. I removed the Cat because of the failure of the warning module/installed a straight pipe. But I'd rather have the Cat and a working module so might have to make that module purchase.

    Dave, where did you get the module?
     
    Rosey likes this.
  4. Dave Bertrand

    Dave Bertrand Formula Junior
    Rossa Subscribed

    Dec 24, 2005
    824
    Castle Rock, CO
    #4 Dave Bertrand, May 13, 2023
    I got mine here - Ferrari part 62347000 - Catalytic Converter Control Unit | Maranello Classic Parts (ferrariparts.co.uk)

    It was $358 last year, I see it's more expensive now. I think I saw a used one for about $250 at Eurospares but I couldn't swear it. I didn't want to ditch the cat since I need it for emissions testing, but I considered doing what Mike did and install a bypass or test pipe. I also considered just disconnecting the dash light, but that was a risk I didn't feel comfortable with. In the end I bit the bullet and made the car right.
     
  5. theunissenguido

    theunissenguido F1 Rookie
    Owner Silver Subscribed

    Jan 21, 2004
    2,686
    Argent/Brasil
    Full Name:
    Guido
    #5 theunissenguido, May 13, 2023
    Be aware there are 2 different models depending your chassis number
    Until nr 76515 its
    part nr 23 on diagram 61402500
    Catalytic Converter Control Unit
    From nr 76529 its
    part nr 44 62347000
    Catalytic Converter Control Unit
     
  6. surfdwn

    surfdwn Karting

    Sep 28, 2005
    140
    Freeport, Fl
    #6 surfdwn, May 13, 2023
    I just came in from cleaning all of the contacts on the controller board. The light now comes on for the self check and then goes off, like it should. I'll take the car out tomorrow to see if everything stays OK. Thanks for all of the feedback. If this takes care of the problem. it will be the third time cleaning contacts has solved a problem on this car. I guess it is to be expected on a 36 year old car.
     
  7. surfdwn

    surfdwn Karting

    Sep 28, 2005
    140
    Freeport, Fl
    #7 surfdwn, May 14, 2023
    I took the car to the hardware store this morning. When I first started it, the Slow Down light came on and stayed on, like it did before. I decided to go ahead and drive the car, as it has been running great. When I started the car at the hardware store, the light came on and then went off after the self check. It remained off on the way home.

    I have ordered a new module. It appears that this one is failing.
     
  8. moysiuan

    moysiuan F1 Rookie
    Silver Subscribed

    Nov 1, 2005
    4,194
    Canada
    #8 moysiuan, May 14, 2023
    You can try taking out the probe in the exhaust and lightly cleaning it with a brass wire brush. Then use Deoxit on the wire connection to the module.

    If this does not work, then the module likely needs to be renewed.
     
  9. ginoBBi512

    ginoBBi512 F1 Rookie
    BANNED

    Oct 9, 2016
    3,535
    SO CAL
    Full Name:
    GINO RUGGIERO
    #9 ginoBBi512, May 15, 2023
    Lose the cat, install a test pipe, its that simple.

    Big G
     

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