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John Deere 550H calibration issues

LWS ยท 2026-08-04 09:59

I have a 2002 JD 550H dozer, I replaced engine speed sensor and the left wheel speed sensor, now it only shifts up to 2.1 speed but everything works otherwise, I tried to calibrate it and that works till I come to step forward. High, then speed goes up to 3.5 but when I put it in forward to calibrate, it soon shifts into 2.1, then when I go to reverse high it only goes up to 2.1 and after that step the red light comes on, on trans controller and calibration stops. codes F8D8 and F3C8 come on. serial # of machine is T0550HX906047, can anyone help me get this figured out. thanks

Replies8
  1. #1mg23612026-08-04 12:36

    Welcome to HEF LWS ! F3C8 Calibration Front PCP F8D8 does not exist. Do you mean F3D8? F3D8 is also for the front PCP The first code could be do to an out of adjustment Null (neutral adjustment). When performing the threshold calibration (that is the one where the tracks just start to move), does the dash light flash a lot longer in one direction than the other?

  2. #2LWS2026-08-04 12:54

    Yes F3d8 is the code, as far as the dash light, I could not tell if it flashes longer in one direction with out doing it again, I would say the dash light flashes in both directions all the time when shifted in during cal. for. and rev. take about the same time when doing the high speed

  3. #3mg23612026-08-05 05:02

    I would check the Null adjustment. If that does not do it, it could be a motor displacement issue. Check your messages.

  4. #4LWS2026-08-05 09:25

    I'll check it out, thanks for your help

  5. #5LWS2026-08-31 11:52

    Hello I got to working on my 550h again I switched the LH and RH drive motor solenoids and the codes switched to F3A8 and F3C8 so it appears one solenoid is bad but I'm confused for sure which one, could you tell me which side to change with those codes or if changing the solenoid is what I should do? thanks

  6. #6mg23612026-09-01 04:49

    Check your messages. Since the code changed with the solenoid, I would be targeting the solenoid that is currently on the right side.

  7. #7LWS2026-09-01 09:58

    Thanks I'll try that

  8. #8LWS2026-09-03 13:05

    I put in a new RH solenoid and it calibrated the first time and all the codes went away and the check service code light went out, everything works perfect now. thank you very much you were a great help to me!!!!