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Deere 544H park brake unresponsive

Discussion in 'Wheel Loaders' started by 02Dmax, Sep 30, 2018.

  1. 02Dmax

    02Dmax Senior Member

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    So I'm working on a parking brake issue on a 544H loader for a customer of mine. The park brake indicator light in the dash never illuminates. The machine just flashes "stop" when you move the shuttle shift lever to "forward" or "reverse" regardless of what position the park brake switch is in. I have 26 volts at the rocker switch in the dash and the switch seems to be working properly. But like I said, the indicator light never lights up and I can't get any power to the park brake solenoid. I do have power to the park brake sensor on the valve and it's getting back to the TCU. Just wondering if it needs a TCU or could something else be causing the issue. I never could find a relay for the park brake either, not even mentioned on the fuse box diagram.
     
  2. partsandservice

    partsandservice Senior Member

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    I am not sure in the 544H application, however on other deere machines I dealt with, there is also a service brake pressure sensor that must show pressure before it will allow release of the parking brake.
     
  3. 02Dmax

    02Dmax Senior Member

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    Thanks, I'll check that out. I managed to come up with a service manual and the one thing I haven't checked is the engine speed sensor which is part of the circuit. Thanks
     
  4. mg2361

    mg2361 Senior Member

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    Check the park brake pressure switch.
     
  5. mg2361

    mg2361 Senior Member

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    Sorry. Just read the entire message wrong and that you checked the park brake pressure switch. I attached a schematic and a solution that might help.
     

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  6. mg2361

    mg2361 Senior Member

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    If the PB light works on the bulb check, then check the F4 fuse. Even if the fuse is good make sure the B02 and P02 red wires on either side of the fuse are good and voltage is getting where it needs to (TCU pins 23 and 68 and the Monitor pin G - unswitched supply).
     
  7. 02Dmax

    02Dmax Senior Member

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    Yep, all that is good. Good continuity on pressure switch, rocker switch, and solenoid harness.
    The park brake indicator bulb does work now, it was just burned out.

    I did get into the monitor and got a 343 and 389 code. Neither will clear because I assume they're active.
     
  8. partsandservice

    partsandservice Senior Member

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    Have you checked the transmission pump pressure. It supplies the park brake release pressure I believe , at least I know it does on a K series.
     
  9. 02Dmax

    02Dmax Senior Member

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    It's not even telling the solenoid to release the park brake. I'm not sure what those codes are, can't find a cheat sheet.
     
  10. partsandservice

    partsandservice Senior Member

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    Just a shot, I recently repaired three zf tranmissions with the same failure. The K series jd. Parking brake would not release. The TCU will abort signal to release solonoid immediately if no pressure signal from park brake pressure sensor. There is not a trans pressure sensor in the TCU circuit. The drive bearing failed and let the torque converter move forward enough to come unsplined from trans pump, and , and it does not have to move much it has very small engagement splines. The other two were case , these did not a affect park brake release because they use the hydraulic system for pressure. Sorry, help you with the codes. The John Deere bookstore has factory manual download s that are reasonable priced IMO.
     
    Last edited: Oct 3, 2018
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  11. mg2361

    mg2361 Senior Member

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    F389 Park Brake Solenoid open. The TCU will send a diagnostic voltage out to the solenoid at key on and if it detects any errors the PB and the transmission are disabled. The F343 Outout Speed Sensor short to power could also create issues. Diag sent to it as well and a faulty output speed sensor will cause transmission to be disabled as well. Check the wiring first. I have seen many issues with the wiring to the output shaft sensor. Park brake could be either wiring or solenoid. Sorry I do not have spec for the solenoid resistance ("J" series is 26 -31 ohms).
     

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  12. 02Dmax

    02Dmax Senior Member

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    thanks a ton, seems like it shouldn't be this complicated to make a loader go forward and backward. haha. I'll check the wiring again to the solenoid. Haven't checked the output speed sensor yet, that code was the first time it indicated any trouble.
     
  13. shadowman1000

    shadowman1000 Member

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    ive got a 544H with a similar problem , park brake will release and work for months , then next day it will not release , shows code 1655 when it doesn't . I have replaced the monitor , CAN from monitor to tcu and ccu .
     
  14. mg2361

    mg2361 Senior Member

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    Sounds like a "CAN" issue. Being intermittent it is probably wiring related. From the frequency of occurrences it will be hard to find as well. From the 544H service manual:

    F1655 No TCU CAN Transmit

    Wire M12 (Purple) Harness (W3) Open
    Load Center Harness (W3) M12 (Purple) Open (Check/Repair.)
    Wire M13 (Purple) Harness (W3) Open
    Load Center Harness (W3) M13 (Purple) Open (Check/Repair.)
    Wire R02 (Black) Harness (W3) Open
    Load Center Harness (W3) R02 (Black) Open (Check/Repair.)
    TCU (A3)
    TCU (Replace)
    MDU (Reconfigure). See Monitor Display Unit Reconfiguration Access Service Menu
    , Machine Model (S 01) , Tire Size (S 03) , Enable Options (S 06) , and Delete Service Codes in Group 9015—15.
     
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  15. shadowman1000

    shadowman1000 Member

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    this has been going on for 5 years , the machine is not used often and sits for months at a time . but when it is used it will work normal for days then the next day it will not release , go to it the next day and all works fine . it had a issue with the monitor ( select button wouldn't work ) and I had local john deere dealer come trouble shoot the parking brake issue and I was told its the monitor ,, so I installed a new monitor . it did not fix park brake problem but it did allow me to see the codes , 1655 ( no TCU transmit ) 1653 ( no CCU transmit )
    The monitor , when its keyed on , will do all the normal light flash and beeps , crank it up , sometimes the PB light will be on and the display will show gear , tach , volts . but when the PB is released the display will only show ----(dashes) for gear position , tach will freeze on what ever rpm it was at . wait , and everything comes back , then goes away . restart it dozens of times with similar results . on rare occasions the PB will release and display is normal but travel 10 feet and it locks down .
    I had a harness from a fire damaged 544J ,I cut it apart and separated the CAN , last friday I piggy backed the second CAN at the MDU , CCU , TCU . that made no change , I then cut the original CAN , again no change .

    why would the engine rpm's freeze ?
     
  16. mg2361

    mg2361 Senior Member

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    All fuses (especially F4) good? Charging system good. Overcharge could cause all kinds of issues. Everything else work (lights, markers, return to dig, etc) when problem happens? Any other warning lights come on when problem happens? I attached a solution that might help. Maybe a screen shot of the monitor when it happens. Also a serial number would help. Dashes for gear position usually indicate a bad FNR or it's wiring. With rpm signal issues check torque converter input speed sensor and it's wiring.
     

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  17. shadowman1000

    shadowman1000 Member

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    I didn't get a chance to get to the machine today , but did stop by the JD dealer and priced associated wiring harness ,wow , no way im going that route . I was able to get into the shop and talk to 2 techs ( ive known them for years) until service manger got back from lunch and told he was going to send me a bill for $200.
    The ser# is 588277 , volts and charging are in range , everything else works as it should and no other warnings..
    Im going to hook up the original CAN and check ohms ( techs told me it should be 60 on the m12-m13)
     
  18. mg2361

    mg2361 Senior Member

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    That was going to be my next recommendation after post #16. If you have 60 ohms (if you have 120 ohms one termination resistor is bad) then check CAN high voltage and CAN low voltage both when machine working normally and when acting up. You want all controllers "in the network" when checking so you will probably have to back probe the wires to check. Normally high would be 2.5-2.7 V and low should be 2.3-2.5 V (the two should add up to 5 V, approx.).
     
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  19. shadowman1000

    shadowman1000 Member

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    I went to the machine today but was only able to spend a hour , the machine is on a restricted site and they were doing HE testing.
    I got the original CAN hooked back up , checked ohms, key off, 63.8 ohms at m12-m13 .. just as I started on my to check list I got told I had 10 mins to leave . I did start the machine , no PB light , dashes on gear display , no tach .
     
  20. shadowman1000

    shadowman1000 Member

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    did some testing today ,still codes 1655 and 1653 , now the park brake light doesn't stay on after bulb check , display still has dashes , no tach and showing volts 24-27 , ohms between M12 and M13 was 64.3 ,, M13 by itself 6.9, M12 by itself 1.8 , RO2 by itself .6 to 1.0 . on the tcu pin 45 wire P-24 had battery volts , tcu pin 23 and 68 wire P-02 had battery volts . G wire at monitor had battery volts .
    whats the TM/SA procedure fix code 1655 and 1653 ? where is the F4 fuse ? I could find no reference to F4 , all fuses checked ok










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