I'd bet that's it. I just wrote it up in another thread "john deere 310SG" but don't know how to link to a different conversation yet.
I'll copy what I found out. It's just duplicate info, but bytes are cheap and it took me weeks and real dollars to get it fixed. You have to have the new controller programmed to your machine. One techy said it could be done at the shop without the machine needing to be there, but another one said that worked sometimes but not always. My new controller wanted the throttle recalibrated or it was unhappy. So unless you have access to JD's factory controller programmer just buying a new part may not work.
Here's what I wrote on the other thread:
"Well, I got it fixed and thought I'd share the results so as to help anyone else with the F450 & maybe F9c4 error code and erratic gauge readouts on their 310SG. It always ran fine, but eventually the temperature gauge would climb to max immediately upon starting the backhoe. That's when I knew something was wrong.
I changed the thermostat sensor (old one was OK), checked the thermostat operation with a thermometer (opens at 180F), and then traced all the wiring for bad connections & shorts.
The standard procedure for resetting the error code wasn't working on my dash readout either.
Went to talk to JD dealer and they said it was probably the engine controller. They saw it a lot on SGs that have the engine controller in the engine compartment where it gets vibration, heat soak, and fluids.....but never at all in later 310s that had the engine controller in the cab as later models had them. The part has had about 6 upgrades according to my dealer, and he is pretty good.
It is roughly a $1600 part & a $100 charge to re-program the new one for the specific 310/ There is also said to be a wiring harness that allows the new engine controller to be moved into the cab where it is standard on newer model 310s. So I figured I'd consider doing that until I found out that the harness to move the controller costs as much as a new controller does. it is the same price as the controller all over again.
BTW, the engine controller also controls the injectors....but that function seemed to be working fine on mine. The only obvious symptom was the F450 error code that couldn't be erased and strange temperature gauge readings.
So I went home and disconnected the engine controller, cleaned all the terminals, checked the wiring again, and reinstalled it. Everything worked fine for about ten minutes and then the gauges went wonky again.
I elected to have the service truck come out and replace the controller. It's an upgrade; the old one is worth a $200 core charge. Replaced the main hydraulic suction hose at the same time and new JD trans/hyd. fluid. Bill just short of $3K. Everything works like new again and the panel readout in the cab is working normally. "
BTW, I bitched about the computer problem and the tech said that the old 310s are actually good or better than the new ones in his opinion. He said the 310SG was one of the last "good ones" in a lot of people's minds. They bring high price used, and that the 310SG was a sought-after machine.
I will say that mine has held up very well. At 5600 hrs it pretty much works like it did new. Engine/tranny/pumps all run fine
rScotty
