John Deere 450H error Code F3H1

[Ernest Stewart]

Dozer starts and hyd works, but when I try to move it I get code F3H1.

The error code F3H1 indicates a problem with the Neutral Start Switch in the transmission controller of your John Deere equipment. It's advisable to check the wiring and connections related to this switch for any faults.

Does anyone know if the neutral switch breaks power to the transmission controller when park brake lever is released, or does it send power to the controller when the park lever is released?

 

[used red MN]

Hello Ernest, welcome to YT! It’s not that you are being ignored, it’s just nobody probably has an answer for you. Did you resolve this or receive help elsewhere? What year was your machine built? I see they were built since ‘99 and still being offered. I know virtually nothing about your dozer. I have watched some videos of guys doing repairs on such equipment. The thing about it is that the switch may not be simply dealing with straight battery power/voltage it is more likely making or breaking a computer/controller reference voltage/signal. Unless someone is extremely familiar with how that system is set up in your machine providing any kind of diagnosis without a manual would prove very difficult. I am also sure the repair manual for those are not cheap. The cost has to be weighed against the expense of what the machine setting there in a useless state costs or what it will cost to have an on-site repair completed.

 

[Jim.ME]

About all you can do with no real info is to check fuses, grounds, and connections. Beyond that you need the Operation and Test Manual (TM1743) and the Repair Manual (TM1744) (about $450 from JD). The Operation and Test Manual should have wiring and hydraulic schematics. No guarantee the manuals will have what you need. It may take get the dealer and hooking up to their computer to diagnose.

 

[Ernest Stewart]

Problem solved. It seems on the start rely other side from the power switch doesn't go to ground there. I tried to bypass the start circuit with a direct wire from the start switch to the relay and grounded the other side. The side I grounded was supposed to go to the transmission controller.

Who knew that was the case? The John Dealer service rep knew, and fixed the problem by connecting the other side of the start relay back to the controller. He told me that when the "ground" side of the start relay doesn't go though the transmission controller, the controller doen't think the transmission is working. Thus the error code F3H1 and no movement.

This is what comes from not having a wiring schematic. Money can ffix anything! lol

 

[used red MN]

Seems to me that grounding a circuit in modern machinery, who’s reaches are unknown to you, particularly one you know is associated with an electronic part like a transmission control module would be a fairly healthy gamble. Seems your happy with the outcome, glad they got it going for you. Thanks for reporting back.

 

[Ernest Stewart]

Aah, but I didn't know the circuit went to the ccontroller. I learned a lesson, but to oredr a $70 service manual was something I tried to avoid.