Hi, first post here. Ive read what i could and still am stumped on how exactly this circuit works. All fuses are good, confirmed the parking brake release switch is good. I did change the parking brake pressure sensor to later put a gauge where the parking brake pressure sensor goes and got zero pressure while running. A quick start up without the pressure sensor in place shows fluid squirting out but not high pressure like its suppose to be (218-260 psi i was told). From the wire for the parking brake solenoid going to the tcu (wire T-09) I am not getting a signal when pressing the switch to energize the solenoid. I tried to jump the pin to a fuse and pressing the switch still nothing. TCU DID have corrosion on two of the pins. I believe one was T-09 and forgot the other one.
Welcome to HEF Felix ! Does the engine rpm appear in the monitor? No rpm signal to the TCU will not allow the Park Brake to release.
The RPM does appear on the monitor. We do have a 524K as well. Are the TCU's swappable?
No. Press the menu button on your monitor until diagnostics (d) is displayed. Press select. Then it should say functional service codes (d1), press select. Record the code, then press next. Record and post all the codes.
Codes were 389, 1664, 341. The 389 might have been from unplugging the solenoid connector but i could be completely wrong. - Nick
This one could prevent you from moving. It is the transmission output speed sensor bad. So the sensor or it's wiring could be an issue. That can be viewed in the monitor. In diagnostics (d), press select. Then to 05, press select. Then next to 056. Does it read zero, or dotted lines? If you can roll the machine with the bucket does it read anything?
Thank you for responding. Under that D 056 it does read zero. If i turn the machine a bit the reading will jump up a little bit and go back to zero. I was told by the other mechanic here that he noticed the input and output rpm speeds were showing a 200rpm difference if that matters.
If you press the select button and hold it for each code, that will clear each code. Then try to run it to see what code comes back. Just for HaHa's, one of the toggle switches on the instrument panel to your right will have a differential symbol (top row, 2nd or 3rd from the right). Turn that switch off to see if that changes anything.
I cleared all the codes, only one to come back right away was F0389 solenoid open. The top row 2nd and 3rd switch from the right are off. No change.
I PM'd you.
Bit of an update to this and need help AGAIN. Confirmed TCU wasnt sending signal from pin T-09 out. Bought TCU, had john deere reprogram it, parking brake now released. Few weeks later it wont release the parking brake again. Only code i get now is F0309. I already replaced the parking brake solenoid. What do i need to check now. This is ridiculous.
Cleared code and now F389 is there and the other code is gone. Im guessing a wiring fault and possibly fried a new tcu. What a joke.
Most likely.