Sensor is in the hydraulic tank.

Thank you

Any idea where the sensor is located?

The code is for hydraulic oil temp. Find the sensor and unplug the connector. check for 5 volts across the feed connector. If you have 5 volts replace the sensor. if you do not have five volts you have an open wire.

I need help... my screen show me 12853. Mast doesnt work, just sometimes like barely... I would appreciate any idea

Yeah, thats what we are doing, thank you for your help its much appreciated..
Art.

ok that is not a good sign but may be the place to start
battery acid is very bad, especially if the motor has a bearing sensor in it.
I would definatly pull that motor and send it out to a motor repair shop and have it thoroughly checked out and rebuilt.
If the acid contamination is too severe though you may wind up having to replace the whole motor if the acid damaged the fields insulation.
I had a Cat A/C E4000 truck do me almost the exact same way as this, it ran me around in circles for a whole day and a half worth of troubleshooting, replacing the logic unit power board and finally finding that the battery overflowed and got acid all over the pump and drive motors, it totally trashed the pump motor due to the acid being so strong because it was a brand new machine.
The operator overfilled the battery before charging and when he did charge it the acid boiled out and went everywhere, ruined their floor and everything.
I would definitely have that motor looked at and repaired, and be prepared, there may be more issues with the fore mentioned controller, the acid could have shorted the circuits and caused damage elsewhere such as in the controller.

Removed the battery and inspected the motor, it's full of battery acid residue and looks like the brushes are in very poor shape as we all as the rotor is in poor shape no shiny copper just black and corroded from the acid..

@ swooped223 the over heating code could be the bad hydraulic pump motor correct.

Yep, removed the side access panels from the floor board and yes it has the electrical switch and wiring connectors under the valve assembly. Not seeing any bad spots on the wiring itself the hydraulic pump is not kicking on at all so, no power stearing or mast controls are working when you jiggle the mast control themselves the pump would kick on. But now nothing I'm starting to think the hydraulic pump motor is bad ? Anyone else have any other ideas..

There are position sensors on the bottom of the valve spools. These sensors communicate with the hydraulic controller. Check the harness that runs to the sensors. There may be a problem with the harness or the hydraulic controller because you are seeing the overheat code coming up.

are you absolutely sure about the switches?
they are/were usually mounted on the linkage bars down near the control valve spools on the link bars themselves.
If they did do away with the standard micro switches they may have replaced them with holographic magnetic switches, or the switches may be mounted on the bottom side of the spool assy's where you cannot see them unless you pull the floor plate and look under the valve assy. There has to be some type of switch there to activate the hydraulic pump when the lever is pulled.
I do not have a VG series truck manual but i do have a GH series which isn't too far behind that one and it shows the same setup that yale has used for years with the switches on the link bars connecting to the control valve spools.

As far as that overheating code yes, check the temperature sensor on the motor and make sure its not shorted or any of it's wiring not damaged. Providing that code is related to the motor and not the controller, if there is no heat sensor on the motor then it's probably a controller overheat code, then you may wind up having to replace the controller since the sensor is inside it's case on the heatsink.

Removed plastic cover and this model has no switches like the older models do.. it keeps tossing code 12853 that's hydrolic temperature is to high but the machine hasn't been used fo get it that high maybe it's a bad temperature sensor that's causing the system to shutdown..

Thanks Art

ERC050VGN48TE085... SER# A968N04126J.
Thanks checking switchs located on mast controls
Thanks Art

yes a full model and serial number would be a big help but a good starting point would be checking the switches and linkage at the lever assy's. The older units had issues with the lever assys that activate the switches would get worn or would get out of adjustment and not activate the switches correctly.
The fact that hyd function works and not works sounds like that may be a good point to start looking at.