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Deere 850c calibration codes rd

N8twny

Member
Joined
Aug 10, 2023
Messages
16
Location
Jamestown New York
I can’t get rid of r and d codes
d is right track motor speed sensor I replaced it and have is set to @ 22 degrees
r is front pump and right motor pcp
Any suggestions how to test pcp
Should I ohm wire out between speed sensor and tcu
Trouble start by not steering left backing up
850c lgp series 2
T0850cx89800. 800 10 software
Thank you
 

mg2361

Senior Member
Joined
Jul 5, 2016
Messages
6,760
Location
Pennsylvania
Occupation
Equipment Mechanic
Welcome to HEF N8twny;)!

Need one more digit in that serial number.

Any suggestions how to test pcp
I do not think your issue is with PCP, yet. When calibrating, did you get to the point the screen says 2Lr? Did the 2 go out?

Should I ohm wire out between speed sensor and tcu
Yes, and check it against the other wires in the harness to make sure it is not shorted to one of them.

Trouble start by not steering left backing up
What codes did you have when this issue was occurring?
 

N8twny

Member
Joined
Aug 10, 2023
Messages
16
Location
Jamestown New York
Serial number T0850CX898000
I can get all the way through the calibration to where I’m supposed to get how frfr when I hit the calibration button to move to the steps of selling the track speed is when I get the little d and little r

The codes I got were
F617 miss Track PCP coil shorted internal linkage I have not gotten this code to reappear after I cleared it nor have I figured out how to check the PCP for this

F620 right track speed motor sensor. I replace the sensor because we thought that was the problem and have adjusted the gap

F635 I believe this is left over from a problem we had a couple years ago we change the sensor because it was drifting when backing up and I did not know how to erase the codes

On the right drive motor PCP harness, coming from the controller just about at the plug. The wire insulation is bad and the short section looks as if when they had the plugs. Zip tied to the PCP. They got hot and the insulation got brittle and split. I made up test harness I get Continuity back to the four wire Deutsch connector where the harness connects to the cab.

A couple of weeks ago, we noticed a hydraulic leak, so I flipped the cab and found the five test hoses for the hydraulics head rub together and were through some of the wires. They did not blow I replaced them, and after about a day, one of the ants blew off that was not crimped enough and made an oily mess under there, I took all the hoses off and had them re-crimped by another Napa store I’ve never had this trouble with houses from them before

Then we ran approximately 20 hours before we had the no backing up turning left problem start

I really appreciate your help
 

N8twny

Member
Joined
Aug 10, 2023
Messages
16
Location
Jamestown New York
I’ve check the voltage at the fuse panel and I get 27.85 is that range of voltage too high ?
at the fuse that goes to the TCU.
Also, I checked the ohms on the PCPs on the left motor right motor and front pump and I’ve gotten ranges that are acceptable to what’s in the service manual94F1640C-FE44-4576-B32B-874DCC32A382.jpeg
 

N8twny

Member
Joined
Aug 10, 2023
Messages
16
Location
Jamestown New York
Does anyone know where I could buy?
JT 07237–4. Four pin, PCP test harness.
JT 07237–1 Single pin, test, harness
Or have instructions on how to build one the John Deere manual I have I do not understand the drawing
 
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