I am looking at a JD 850J Lt with 2 active codes TCU 1071.6 fan drive sol short circuit TCU 522439.5 Tank bypass sol no response Owner says he hasn’t worried about them because nothing has changed in the operation of the dozer What is the level of trouble with those codes? Look forward to hearing your opinions Thanks
Machine serial # T0850JX117104
The 1071.06 code will cause the fan to run at full speed all the time. If the noise doesn't bother the operator, it will not hurt anything. However, proper engine/hydraulic temperature control will be compromised. 522439.05 code will set at start up. That solenoid being out of the loop will cause almost all the oil to go through the oil cooler all the time, again, affecting proper temperature control of the hydraulic oil. I see you are in Canada? I would be worried about overcooling. Oil will stay thicker, which could affect lubricity, case drain pressures, cause cavitation, etc. If you were in Florida, I would say you would very little issue.
Ok thanks for the info! Pretty tough to diagnose before a person buys it as to what could be causing the code?
What all is involved in that trans coolant circuit? Could it end up being quite expensive for parts?
Either code is an electrical issue, either with the solenoids, or it could be a wiring issue to the solenoids. Just the solenoid coils (which can be bought separately) will run close to $150 US each.
Ok thank you, appreciate the knowledge