Service Code List for 310SG

[rScotty]

Anyone have a list of JD310SG service codes and what they mean? My dash readout "Service Code F450" the other day.

Here's the history: Good machine, regular maintenance, 6000 hrs. No problems.
In cold weather I usually plug in the block heater on our JD310SG TLB before starting it. The motor always starts up immediately even down below zero, but I would rather heat things up with the block heater first.

After it starts, it's been my practice to let it idle for half an hour or so to warm the cab and get fluids flowing.

But yesterday when I did that I saw that instead of giving me the RPM, voltage, & pressure, the digital readout read "Service Code F450".
By the time I got in the cab and settled down, the message was gone - but I think it returned again later in the day for a few minutes - not sure of that.
Everything under the hood seems normal. The fluids are all normal.

So what does Service Code F450 indicate? Anyone know?
thanks, rScotty

 

[rScotty]

Here's an update. What's happening is that the JD 310SG backhoe runs fine and doesn't overheat. But during the warmup at idle after about 5 minutes the temperature gauge begins to climb rapidly to the top of the scale. That sets off alarms and throws service code F450. I'm told that code is for the temperature sensor on the thermostat and indicates zero voltage at the sensor.

None of this makes sense to me. There's plenty of good coolant, the engine runs well and doesn't seem to be overheating, but the tractor thinks it is getting too hot.
Any ideas?
rScotty

 

[chevy791979]

Here's an update. What's happening is that the JD 310SG backhoe runs fine and doesn't overheat. But during the warmup at idle after about 5 minutes the temperature gauge begins to climb rapidly to the top of the scale. That sets off alarms and throws service code F450. I'm told that code is for the temperature sensor on the thermostat and indicates zero voltage at the sensor.

None of this makes sense to me. There's plenty of good coolant, the engine runs well and doesn't seem to be overheating, but the tractor thinks it is getting too hot.
Any ideas?
rScotty

I have seen this code 100x on these backhoes, and I'd be will to bet the ECU is bad. One way to tell is look at it (left side under the injection pump) and see if it has a bulge and it if fuel has leaked on to it. Also you can remove it and with it still hooked to the wiring harness, key on engine off, LIGHTLY tap it against the engine or frame and watch the temp gauge. If it changes at all you have bad ECU.

 

[rScotty]

I have seen this code 100x on these backhoes, and I'd be will to bet the ECU is bad. One way to tell is look at it (left side under the injection pump) and see if it has a bulge and it if fuel has leaked on to it. Also you can remove it and with it still hooked to the wiring harness, key on engine off, LIGHTLY tap it against the engine or frame and watch the temp gauge. If it changes at all you have bad ECU.

Ah..... thanks a million for that response, chevy. I had just about come to the same conclusion because of several things. My local service shop says that the SG series had problems with the EC units. But the EC swap is $1500 plus a programming fee and a $300 house call and no guarantees......so I've been playing with it myself. Want to be absolutely sure what I'm asking for before a $2K service call. Took the sensor out of the thermostat compartent and checked its resistance in hot water vs a new sensor - they are the same. Also I get 5v. at the sensor with key on but it changes to near zero volts when running for ten seconds now. That indicates hot, but isn't realistic. I have not changed the thermostat - although I do have a new one sitting here.

Reason I haven't changed it is that now things have changed. the temp gauge is climbing to full hot within ten seconds of my starting the engine from overnight cold....so I am also thinking it is the Engine Controller. Just on a "why not?" I tried to cancel the error code in the EC but cannot get the EC into its internal menu mode at all. I think that is normally done by holding the Select (select mode) button down 5+ sec. with key on. But I get nowhere doing that.

I'm considering putting in a manual temp gauge& just use it at least until next Fall before getting a new EC. Near as I can tell, the EC doesn't actually control anything in the engine. It seems to simply take sensor data and display it on the screen. I wonder if it has any other functions? How to find out??

I'm going to do as you suggest and take a closer look at the EC. It looks OK & doesn't show sign of being dripped on, but who knows. I'll also tap it to check connections. Good idea.
Thanks again,
rScotty - favorite recent chevy is our old '70 PU.

 

[chevy791979]

Ah..... thanks a million for that response, chevy. I had just about come to the same conclusion because of several things. My local service shop says that the SG series had problems with the EC units. But the EC swap is $1500 plus a programming fee and a $300 house call and no guarantees......so I've been playing with it myself. Want to be absolutely sure what I'm asking for before a $2K service call. Took the sensor out of the thermostat compartent and checked its resistance in hot water vs a new sensor - they are the same. Also I get 5v. at the sensor with key on but it changes to near zero volts when running for ten seconds now. That indicates hot, but isn't realistic. I have not changed the thermostat - although I do have a new one sitting here.

Reason I haven't changed it is that now things have changed. the temp gauge is climbing to full hot within ten seconds of my starting the engine from overnight cold....so I am also thinking it is the Engine Controller. Just on a "why not?" I tried to cancel the error code in the EC but cannot get the EC into its internal menu mode at all. I think that is normally done by holding the Select (select mode) button down 5+ sec. with key on. But I get nowhere doing that.

I'm considering putting in a manual temp gauge& just use it at least until next Fall before getting a new EC. Near as I can tell, the EC doesn't actually control anything in the engine. It seems to simply take sensor data and display it on the screen. I wonder if it has any other functions? How to find out??

I'm going to do as you suggest and take a closer look at the EC. It looks OK & doesn't show sign of being dripped on, but who knows. I'll also tap it to check connections. Good idea.
Thanks again,
rScotty - favorite recent chevy is our old '70 PU.

The ECU does control fuel delivery and injection timing.

 

[chevy791979]

Check continuity on B1 ecu connector and terminal A of the cool temp sensor. And D3 ECU and B of temp sensor connector. Should have close to zero ohms. Please don't force DVOM leads in the terminals of any connectors. It is very easy to do if you don't have the right test leads. And don't over torque the 1/4 is boot that holds the connector on the ECU itself.

 

[chevy791979]

If those wires and terminal are good. The ECU is bad

 

[rScotty]

If those wires and terminal are good. The ECU is bad

Good info, thanks. So to check...., I'll take the ecu off the block, remove the end connectors (1/4" bolt) and check between the inside of the ecu connector and the other end of the harness where it plugs into the sensor. Correct?
BTW, what pubilcation are you looking at for those photos? I need to get one.... I can't believe how hard it has been to get tech info on the JG310SG compared with other tractors. I feel like I'm in the twilight zone and there must be a hundered thousand of that model out there.

uh.... How in the world? What mechanism does the EC use to control fuel delivery? I ask because the engine has what looks just like a basic mechanical fuel pump, and the injectors are straight mechanical. Now I grant that there are two wires going into that fuel pump from somewhere....and that "somewhere" sure could be the ECU. My thought when I saw those wires was since the wires are the same smallish diameter as the other sensor (coolant temp and turbo temp) wires, so I figured they were just doing some sort of sensing....maybe RPM sensing. To carry it a step farther, I was thinking that any type of active fuel control I could imagine ought to show up as a wire sized for enough amperage to work a solenoid at least.

BTW, I have a ton of Yanmar info & a bit of knowledge there if needed.
rScotty

 

[chevy791979]

Good info, thanks. So to check...., I'll take the ecu off the block, remove the end connectors (1/4" bolt) and check between the inside of the ecu connector and the other end of the harness where it plugs into the sensor. Correct?
BTW, what pubilcation are you looking at for those photos? I need to get one.... I can't believe how hard it has been to get tech info on the JG310SG compared with other tractors. I feel like I'm in the twilight zone and there must be a hundered thousand of that model out there.

uh.... How in the world? What mechanism does the EC use to control fuel delivery? I ask because the engine has what looks just like a basic mechanical fuel pump, and the injectors are straight mechanical. Now I grant that there are two wires going into that fuel pump from somewhere....and that "somewhere" sure could be the ECU. My thought when I saw those wires was since the wires are the same smallish diameter as the other sensor (coolant temp and turbo temp) wires, so I figured they were just doing some sort of sensing....maybe RPM sensing. To carry it a step farther, I was thinking that any type of active fuel control I could imagine ought to show up as a wire sized for enough amperage to work a solenoid at least.

BTW, I have a ton of Yanmar info & a bit of knowledge there if needed.
rScotty

I work for John Deere construction dealer. I'm using service advisor.

You should have a two wire sensor at the top of the inj pump for fuel temp. The one that is in the center of the injection lines is the injection pump solenoid. It used to meter the amount of fuel aloud into the injection pump Chambers. It is a pulse width style solenoid And in turn that also acts as a shut off solenoid.

 

[rScotty]

I work for John Deere construction dealer. I'm using service advisor.

You should have a two wire sensor at the top of the inj pump for fuel temp. The one that is in the center of the injection lines is the injection pump solenoid. It used to meter the amount of fuel aloud into the injection pump Chambers. It is a pulse width style solenoid And in turn that also acts as a shut off solenoid.

I wonder if I can get a copy of service advisor. Is it digital, interactive, or printed?

Yes, I understand pulse width type solenoid control from some mech/magnetic work I've done. Darn.... that would explain active control. May be an ECU in my immediate future afterall. Going to do your tests this evening or tomorrow.

I'm still first going to check the true engine coolant temperature with an independent source: I.e. a bulb type thermometer sender just to make sure there isn't something there.
BTW, doing that has required a bizarre brass fitting to get from the 14Mx1.5 thread of the sensor sender to the standard 3/8" tapered pipe thread of the gauge.
If I were more up to date mechanically I'd probably use an IR gun on the alum. thermostat housing .. that is IF I had an IR gun.... I'll have one by next week, though. Any excuse for another tool.
..
I am doing all this extra temp check partly for curiousity & partly because of my reluctant to change thermostat for new one because I have never fitted up JD's peculiar half-inch steel bypass tube from water pump. Local JD shop said just flex the tube out of the way and put new rubber sleeve in the housing.....but that sounds strange to me. I considered cutting and hose-splicing that silly tube. I do have new rubber sleeve, but have never used that type of sleeve and don't know if it goes into thermostat housing first or put it onto the tubing and force it into the housing. Whatever the case, it just doesn't look like a very leakproof connection to me & reluctant to mess with mine. Am I being too shy?
Thanks for all,
rScotty