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Active TCU Code Deere 850J

sfowler

Active Member
Joined
Dec 7, 2019
Messages
44
Location
S. Texas
850J dozer Ser. 169801. I check for active codes periodically and there was one listed today. It said " Cooler Bypass Sol No Response TCU 522451.5" Does anyone know what this is? As far as I can tell there was no affect on the machine while I was running it and there were no warning or caution lights lit up on the panel. I ran out the day without any problems that I know of.

Thanks
 

mg2361

Senior Member
Joined
Jul 5, 2016
Messages
5,259
Location
Pennsylvania
Occupation
Equipment Mechanic
Code definition is: Hydrostatic oil cooler bypass solenoid (Y16) is open or short to power. Take a picture of the big block that is inside the left rear access door and post.

Also, what is the letter before those 6 digits of that serial number?
 

sfowler

Active Member
Joined
Dec 7, 2019
Messages
44
Location
S. Texas
Code definition is: Hydrostatic oil cooler bypass solenoid (Y16) is open or short to power. Take a picture of the big block that is inside the left rear access door and post.

Also, what is the letter before those 6 digits of that serial number?

full ser. no. T0850JX169801

Working on getting a pic
 

sfowler

Active Member
Joined
Dec 7, 2019
Messages
44
Location
S. Texas
Code definition is: Hydrostatic oil cooler bypass solenoid (Y16) is open or short to power. Take a picture of the big block that is inside the left rear access door and post.

Also, what is the letter before those 6 digits of that serial number?
02C3EFE3-FF0C-4C54-B13B-107833457432.jpeg 622929B9-2818-47CE-A582-73F02B7B51D1.jpeg
 

sfowler

Active Member
Joined
Dec 7, 2019
Messages
44
Location
S. Texas
Solenoid ohmed out at 28.6/79F which seems reasonable with the specs you shared. Ran the machine all day with no active codes. 'Stored Codes' function shows 11 occurrences for this fault in the last 300hrs. I will trace out the wiring when I get the cab tilted. Is there any harm in running till I can get the machine back to the shop for maintenance? I'm guessing the solenoid has some sort of temp regulation function (maybe helping warm up the hydrostat oil on colder day start ups?)

Thanks Again
 

mg2361

Senior Member
Joined
Jul 5, 2016
Messages
5,259
Location
Pennsylvania
Occupation
Equipment Mechanic
Is there any harm in running till I can get the machine back to the shop for maintenance?

No harm so long as it is not overheating.

I'm guessing the solenoid has some sort of temp regulation function (maybe helping warm up the hydrostat oil on colder day start ups?)

Correct. Helps with warm up and when the oil starts getting hot the controller starts to de-energize the solenoid which directs more oil through the oil cooler.
 
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