EU 355 M5.2 SLOW DOWN | Page 2 | FerrariChat

EU 355 M5.2 SLOW DOWN

Discussion in '348/355' started by Ricambio, Oct 30, 2019.

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  1. Qavion

    Qavion F1 World Champ
    Silver Subscribed

    Feb 20, 2015
    11,484
    Sydney
    Full Name:
    Ian Riddell
    Strange. I've had no problems with a $10 Fiat adaptor and a relatively cheap scanner (less than U$100) I found on eBay. This is the basic wiring for the adaptor

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    Unfortunately, I think we are running out of suggestions. If it's not a faulty thermocouple, or a thermocouple wiring or a thermocouple ECU wiring issue, then there it has to be a Motronic ECU problem. If the Motronic ECU won't talk to the scanner, then perhaps it is a ECU problem. I would try a different scanner and adaptor first, however.
     
  2. yelcab

    yelcab F1 World Champ
    Consultant

    Nov 29, 2001
    12,661
    San Carlos, CA
    Full Name:
    Mitchell Le
    Ricambio,

    So there is no OBD2 connector under the dash near the steering column?

    By the way, you should disclose more information in your profile. Where are you located?
     
  3. yelcab

    yelcab F1 World Champ
    Consultant

    Nov 29, 2001
    12,661
    San Carlos, CA
    Full Name:
    Mitchell Le
    What have you replaced?
     
  4. Ricambio

    Ricambio Karting

    Dec 30, 2016
    76
    We replaced (swaped from other working 355) the CAT modules, but didn't swap the thermocouplers, we measured both cars (sensors) in cold and they were equal resistance. All the connections (wiring contacts) were OK as we wanted to trace a probably faulty contact in the wiring but didn't find anything loose.

    I just recieved my other 3 PIN FIAT cable with + & - clamps to power it up and will try it with the scanner. I will report back.
     
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  5. Ricambio

    Ricambio Karting

    Dec 30, 2016
    76

    NO OBD2 connector present in this euro 1996 F355.. unfortunately :/ (Peru)
     
  6. yelcab

    yelcab F1 World Champ
    Consultant

    Nov 29, 2001
    12,661
    San Carlos, CA
    Full Name:
    Mitchell Le
    On the 5.2 version, if there is a noisy thermal couple or an intermittently bad TCU that results in a spike in output voltage to be higher than the second limit, the main ECU turns on the SD permanently and logs an error code for that TCU. That error code does not force a CEL, but it is logged permanently. Each time the car starts up, the main ECU sees the error code and turns on the SDL again even if the output of the TCU has fallen back into good range.

    To get SDL to reset, you have to clear the error code with your OBD2 connector and scanner. Turning power off alone does not clear the code.

    You should change the thermal couple, and find a way to clear the SDL error code. Good luck.
     
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  7. m.stojanovic

    m.stojanovic F1 Rookie
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    Dec 22, 2011
    2,743
    Malaysia - KL
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    Miroljub Stojanovic
    Checking resistance of the Thermocouple sensor is not really the way to test it. The proper way is to take it out, connect a multimeter/voltmeter (set at mV range) to the Thermocouple wires, positive to the WHITE wire and negative to the RED wire, and heat the Thermocouple tip with a torch. Don't be afraid to heat the tip up to bright red but don't overdo it. You should get some 5-6 mV when cold and ~35 mV when bright red showing continuous voltage rise between the two figures during heating. If the voltage rise is not continuous but shows spikes or breaks, the Thermocouple is bad.
     
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  8. Ricambio

    Ricambio Karting

    Dec 30, 2016
    76
    Thanks for the input and you are correct by deleting the DME to get rid off the slowdown light. Here's what I found:

    Got a ebay 3 PIN cable converter , hooked it with a 12v battery to power it up and connected it to my Autel scanner. Clicked the F355 model and then the Motronic Bosch and same thing, it won't recognize....then I selected the OBD2 connection (manually) in that option into the scanner, and tried pretty much every protocol of connection, finally found the right protocol, it's ISO 9142-2. It's curious that we tried all these protocols of communication with the genuine FIAT OBD2 adapter (3PIN) from the very own brand of the scanner and didn't work.

    Although, the info that gives the DME is very VERY basic, we checked for faults and the system couldn't detect any DTC stored, so I went ahead and deleted the DTC error for the sake of it and voila! The next re start of the engine the SLOW DOWN red light was gone! So you were right. Now I wish this scanner with this ebay connector could read the TEVES system, SRS and suspension modules but won't doit evenconnecting the 3 PIN cable in every terminal connector of each system.



    Thanks for the detailed info, I will look into that and report back.
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  9. Ricambio

    Ricambio Karting

    Dec 30, 2016
    76
    Thanks for the detailed info, I will look into that and report back.
     

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