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JD 304H code ER04

Discussion in 'Wheel Loaders' started by rrrawhide, Oct 9, 2019.

  1. rrrawhide

    rrrawhide New Member

    Joined:
    Oct 9, 2019
    Messages:
    3
    Location:
    Browning
    Have a John Deere 304H loader throws code ER04, JD tech says it is parking brake. Have changed parking brake switch many times, it will work for awhile but then locks everything up. Have to turn master switch off for awhile sometimes it takes off sometimes it takes several atttempts. JD said to try new monitor so $2500 later because parking brake light and seat belt light would flicker, everything was working fine for about 10 hours then it started up again. I am so frustrated, changed trans filter/fluid, checked brakes and fluid. Any help would be greatly appreciated, thanks.
     
  2. mg2361

    mg2361 Senior Member

    Joined:
    Jul 5, 2016
    Messages:
    899
    Occupation:
    Equipment Mechanic/Technician
    Location:
    Pennsylvania
    Welcome to HEF rrawhide;)! First thing to do is unplug the park brake pressure switch and place a jumper between terminals A and C of the wire harness connector. If the machine works properly then you have another bad PB pressure switch. If it still acts up plug it back into the switch and then swap the park brake pressure relay (may be marked K22) with another relay and test again. How handy are you with a voltmeter? Perform the above steps first then we'll continue from there.
     
    thepumpguysc likes this.
  3. rrrawhide

    rrrawhide New Member

    Joined:
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    3
    Location:
    Browning
    I tried the jumper, nothing. I swapped relays with another relay (fuel shutoff) nothing. I know how to use voltmeter, Thank you for all the help, I need to get loader running before next snow storm hits.
     
  4. mg2361

    mg2361 Senior Member

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    Are all the pins in the Monitor connectors in good shape and not spread? When you shift into either Forward or Reverse do the UP and DOWN arrows on the monitor light up?
     
  5. rrrawhide

    rrrawhide New Member

    Joined:
    Oct 9, 2019
    Messages:
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    Location:
    Browning
    Yes, the pins in the connections look to be good, when I start it up the parking brake light gets faint not bright like it should be, turn off parking brake switch and shift into gear and it goes straight to ER04. No arrows and it is locked up. thanks
     
  6. mg2361

    mg2361 Senior Member

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    Occupation:
    Equipment Mechanic/Technician
    Location:
    Pennsylvania
    If you back probe pin A (carefully as to not damage the pins) of the PB pressure switch with the engine running what is your voltage. Then do pin B and C. Check all the voltages with the PB engaged and in the released position. Post results.
     
  7. mg2361

    mg2361 Senior Member

    Joined:
    Jul 5, 2016
    Messages:
    899
    Occupation:
    Equipment Mechanic/Technician
    Location:
    Pennsylvania
    Read posts again and I don't like the fact that the light is dim and flickers. Check the load center (where fuses and relays are) ground which should be below the fuse panel. It is hard to see and get to but there has been issues there. Make sure there is no paint on the bolt boss for the ground. Make sure to remove the bolt and clean everything and reinstall being mindful of the heat shrink on the eyes and that the heat shrink does not interfere with the connection. Also check the CN3 and CN5 connectors (green I think, board is labeled) and its terminals for fit and cleanliness. Check the CN7 (white I think) connector and terminals as well. Check the X5,6 and 7 posts on the load center for battery voltage. Anything less than 10 volts would be an issue. If all checks OK then proceed with instructions in post #6 above.
     
    Vetech63 likes this.