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DTC Gearbox P0501 won't delete

Discussion in 'FF/Lusso/F12/812S' started by fhmmax, Nov 20, 2017.

  1. fhmmax

    fhmmax Rookie

    Aug 4, 2016
    6
    Trying to work out how to delete the code on my FF. Tried everything from erase (using Ferrari computer) to removing the battery and putting a new one in .

    Long story short i have had the Speed Sensor code P0501 for a while, it doesn't bring up any CEL or problems in anyway BUT its there in the computer and bugging the crap out of me so if anyone knows a trick to get rid of this deep routed fault code i would be grateful. So far tried everything including pressing 69 buttons at one time while rolling my trouser leg up and wearing a deer hat but still there.
     
  2. Motob

    Motob Formula 3
    Professional Ferrari Technician

    Nov 11, 2003
    2,165
    Berkeley, CA
    Full Name:
    Brian Brown
    Umm, It's because you have a problem with the speed sensor that needs to be diagnosed and repaired. There is no trick to erasing a code if there is a problem in the transmission that is setting the fault.
     
  3. fhmmax

    fhmmax Rookie

    Aug 4, 2016
    6
    normally i would agree but car is showing no signs of a problem, no lights, no problems with gear change, speedo works fine etc. It was simply when i did a full diagnostic that i found it, and there is no way i will give Ferrari 10k just to open a box and change the sensor. I wanted to clear the code to see if it would come back that way i know for sure there is something i have to dig deeper into.
     
  4. Motob

    Motob Formula 3
    Professional Ferrari Technician

    Nov 11, 2003
    2,165
    Berkeley, CA
    Full Name:
    Brian Brown
    You should be able to clear the code, as it is a speed sensor code. Even if the speed sensor is faulty (The P0501 code is output speed too high), it should only set after driving the car. Can you clear the code using the Ferrari tester? If the code doesn't clear, then you have another issue, it should clear and the only come back after driving the car.

    You can drive the car if it doesn't manifest itself as a problem, but at some point the speed sensor may start to cause a shifting problem and then you are going to have to replace it. It is a level 3 repair, which means the entire transmission must come apart (gears, shafts, synchronizers, etc. so it is the most labor intensive and most expensive. Plan on more than $10k for the repair.
     
  5. fhmmax

    fhmmax Rookie

    Aug 4, 2016
    6
    This is my point why i don't want to give Ferrari 10k yet. The code won't clear (which it should) even tested speed sensors on the wheels for voltage and they are all good. The only thing i can think of is that it is a grounding issue or some other electrical short because removing the battery should have cleared it even if the computer didn't.
     
  6. 350MH83

    350MH83 Formula Junior

    Jul 11, 2014
    314
    France
    Full Name:
    Max
    It doesnt look like it's a wheel speed sensor. Rather a transmission speed sensor. There might be a way to test the transmission speed sensor without dropping the transmission... Like from the other end of the wiring going to the speed sensor. It might be much more complicated than that though.
     
  7. 350MH83

    350MH83 Formula Junior

    Jul 11, 2014
    314
    France
    Full Name:
    Max
  8. Motob

    Motob Formula 3
    Professional Ferrari Technician

    Nov 11, 2003
    2,165
    Berkeley, CA
    Full Name:
    Brian Brown
    The P0501 fault is caused by the output speed of the shaft inside the DCT transmission being too high. If you cannot clear it when the car is stationary with the engine off, then there is some software or communication glitch with the DCT ECU. Further investigation is needed. Possibly a proxi alignment or software update?

    The photos that 350MH83 has posted are of a speed sensor/connector from an F1 tranmission, not a DCT transmission. The electrical connector for the speed sensor on the DCT transmission has 16 pins. The although there is one part called the speed sensor, it incorporates three hall-effect sensors in one unit. They measure the even-shaft speed, the odd-shaft speed and the output shaft speed. There is a separate sensor located in a different spot that measures the input shaft speed from the engine. I don't know what kind of diagnostic computer that you are using, but with the Ferrari DEIS computer you can look at the speeds of all of these sensors and the supply voltage to the sensors. If the sensor had no output or had a problem with wiring/electrical connections, then you would get a P0503 code, which is "no signal from the output sensor" The P0501 fault is usually accompanied by other speed sensor faults when the sensor goes bad.

    You need to be able to clear the code and then drive the car to see if there is really a problem with the sensor before doing any repairs to the transmission.

    If you cannot get it to clear and it doesn't have any shifting problems or lights coming on, then I would just drive the car. If there is a problem with it, it will only get worse, but it is not going to damage any other component in the transmission.
     
  9. 350MH83

    350MH83 Formula Junior

    Jul 11, 2014
    314
    France
    Full Name:
    Max
    Thanks for the feedback Brian.

    The pic I posted is coming from the FF maintenance manual, so I thought it would be correct. I havent checked on a car though!
     
  10. fhmmax

    fhmmax Rookie

    Aug 4, 2016
    6
    thanks guys, i have the workshop manual, guess i was being lazy before getting my hands dirty. On the plus side though i just got the best Black Friday deal ever with 53k off a brand new Bentley Bentayga, down side it was a 2017 model, upside there is no difference what so ever with the 2018 model lol.
     

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