Probably has a bad computer module under the dash OR there is a bad connection between it and the magneto kill wire.


Sent from my iPhone using Tapatalk

 

There are two ways the X300 shuts down normally, the fuel shut off solenoid and the Magento kill wire. They are both controlled by the ECU/TDM.

I would fine the (typically) white wire that goes under the shroud and to both coils and make sure it is connected.

Most likely, it is the ECU that is bad. That is probably $100, so expensive to replace if it is not the problem.

 

The wires going to the coils are connected and if I disconnect while running..... it still keeps running! One wire goes to the coils and the other powers the fuel solenoid on the bottom of the carb but shouldn't the engine shut down when the wire is disconnected to coils?

 

No, the coils wire is a "kill" wire. Ground it and the engine should stop running, since it will no longer get spark.

The fuel solenoid is an automatic cutoff. So, if you remove the wire from it, it should cut off fuel supply. But, sometimes people cut the tip off, to solve/troubleshoot a no start issue.

If removing the fuel solenoid wire causes the engine to shut down and/or grounding the wire to the coils causes the engine to shut down, that points a strong finger to the ECU module.

 

I will be grounding the coil wire tomorrow to see if it dies which it should (didn't try that today) when this started today, I also noticed excess fuel coming out of the carburetor. Thanks for the advice and I'll update tomorrow

 

UPDATE:
I just started it and grounded the coil terminal and it shut down right away

 

That means either the wire isn't connected to the computer (ECU) or the computer is not doing its job. Check connections first. If it still doesn't shut off, you probably need a new ECU.

Will it start with the brake off?

 

It does not even turn over with brake off

and I have continuity going to one of the pins on the ECU from black wire going to coils.

 

I would like to point out that, if you disconnect the power wire to toe fuel solenoid while running, it will take a few seconds to run out of fuel. Mine was like 10 seconds until it died.


Sent from my iPhone using Tapatalk

 

I think Frogmore pointed out earlier that some people cut the tips off so in my case, I believe the previous owner did this as when i disconnect power wire going to fuel solenoid, the machine continues to run even though I still hear the solenoid click when the key is turned on.

 

I would say you seem to have done enough troubleshooting to say it really sounds like the ECU is not activating the kill wire. That probably means the ECU is bad.

 

thanks guys so much for the input, you steered me in right direction as I was originally looking for ground wires that I assumed the stop switch went directly to ground? Way to easy that way! Instead of going through an expensive $160 module up here in Canada! Anyways, thank you!

 

I suppose you could wire up a kill switch if the ECU is doing everything else you need. It might work okay for awhile longer.

Probably not a good long term solution.

 

That's what I would do. With the intent of fixing in the near future. But, when my solenoid died, I clipped the tip off with the intent of just getting through the week end. That was over ten years ago, and it's still running fine, so I never fixed it properly. As my Dad would say, "Do as I say, not as I do". I'd recommend the proper fix eventually, the kill switch just temp.

 

Probably should make it a momentary switch, or you will be back with a no start issue soon 😉

 

So after looking at things once again before I buy an ECU, I did notice a loose wire that someone had done a **** poor job of jumping (or whatever they were trying laying there with one broken connector and loose wire on the other end so I'm kinda back to square 1 until I figure out where it's supposed to go. Looked for a detailed wiring diagram but didn't find one. I'll post some pics of my setup hoping someone may be able to shed some light on it or send me a detailed diagram? Pic of loose wire which wasn't in any conduit and only about 12" long.... and appeared to come out of the ignition switch.... also moted there is no wire coming out of M socket and I believe when the key is in stop position it switches ground to M to cut coils and ground? other pics to follow and I'm a little slow at this lol

 

This is a pic of the ignition switch wiring

 

And finally,

a pic of the large wiring harness located between the 4 fuses and the deck engage/disengage switch, also, if I didn't mention, I just tried the deck and it's not working. So both issues came up at the same time with the tractor not shutting off (ground not going to coils) and (deck not working)

 

I don't have a schematic for the X300, but I do have one. It does not appear to actually use the M terminal on the key switch and does not have a ground wire to the key switch. I do have a schematic for the X500, but there are several and it is not really clear about that terminal, but looks like no connection. Since the engine runs for several seconds after turning off the key, it is clear the ECU/TDM/interlock module (it is called all of those names in different places) is responsible for turning off the fuel solenoid and activating the kill switch. It is also responsible for turning on the PTO based on several signals. So, it seems pretty clear it is not doing all that it should.

Without the TSM, you are guessing, but it is a really good guess that the module is bad.

You can sometimes find a service manual on eBay for a reasonable price. Or, you can just buy the module. I have heard they have a high failure rate, but mine have been fine.

 

I'm willing to replace it no problem but was concerned about the wire laying there that was plugged in (I assume) but fell out. I will pick up a new ECU tomorrow and see what happens

 

I have the service manual.


Sent from my iPhone using Tapatalk

 

If your able to take some pics of wiring diagrams and send to me I’d really appreciate it! I’ll probably buy the ECU anyway and maybe hold off on installing it until I figure out where that loose 12” wire goes. The ECU with tax is $180.00! Your welcome to email me at your convenience at hottubrepairman@yahoo.com TIA

 

Here is a schematic. Not sure if years covered. Fits my 2010

 

Thanks for that. I have several wiring diagrams but none show where the load side of the middle fuse on LEFT connects to? The wire from the load (LEFT SIDE) fell out and was laying there so I'm not sure where it's supposed to connect to as the other end of the wire fell out of where it's supposed to go also.

 

That shows 4 wires on the key switch. Looks like it says 2 are white and 2 are red. Most of the other schematics use red and yellow. But, none of them show using the M tab and ground, so that is not what actually stops the engine.

You will have to do some digging to figure out where that red wire was hooked up and if it was original or something the PO tried to work around the starting to fail ECU.

 

So I have an update now....
-I went to the Deere dealer to buy a new ECU and the guy was nice enough to try it on another one and it worked fine so I didn't bother buying a new one and started looking back at the Red wire that was loose.

Current issues -engine shuts off intermittently but does work and that's the least of my worries now and I'll deal with that later. The big concern I now have is the deck not engaging (from what I understand the correct term is PTO) I've done a lot of troubleshooting and reading the past few days without the exact wiring diagram I need but am willing to buy one if I have too.

What I've found- fuse box fuses all tested and fine but found NO CURRENT going through the second fuse down from the top and after further inspection, I found that the terminal that connects the load side of the fuse is missing in the box?? Note that the top and bottom both have load side wires going to where they're supposed to but the middle load terminal and wire are gone. Pretty sure that's where my RED WIRE came from that was laying there as I said earlier. I'm going to temporarily jump the fuse to wherever the other end goes too which is unknown as I don't have a correct detailed wiring diagram specific to mine PRODUCT IDENTIFICATION NUMBER (M0X300C104178)

I'm going to post a pic of the Red wire that was loose when the problems began as well as the fuse box OPPOSITE SIDE OF THE FUSE SIDE which you can see the right side is the power supply from the battery and the middle fuse (2nd down from top) does not have a wire or terminal in the block load side of fuse anymore and I'm positive that's where the RED WIRE came from as the terminal tip on the RED WIRE that broke is gold, unlike all the other connectors. I just need to know where the other end goes so I can jump it to confirm this is the issue so I can order the parts I need to complete the repair properly unlike the previous owner. If anyone is able to shed a little light on this, look at your fuse box wiring or point me in the right direction of the correct wiring diagram, I'd really appreciate it! As I said its a John Deere X300 PIN- M0X300C104178. Thanks in advance if anyone can help me out! Hope I've explained things well enough, If not feel free to ask, Thanks

 

That is not a missing wire on the right hand side. All three terminals on the right side are connected together and to the one red wire that is there.

You REALLY need a schematic to make sense of a complex electrical circuit, especially one that might have been modified by a PO (that might or might not have known what they were doing).

It appears that the ECU you have is not defective, since it worked okay on the other tractor. You can usually find a service manual on eBay. It might or might not be the same as what you get from Deere. See my thread on X700 series radiators and how I almost spent $600 on a radiator I don't need, because I was SURE mine was bad and didn't want to spend under $100 to be REALLY sure.

If you have a great deal of experience in electrical matters, it is possible to figure things out without a schematic. Decades ago, I fixed a car amplifier of mine. The first thing I did was trace all the wires to create a schematic, since none was available for any price.

The TSM from Deere is expensive, and I don't believe it is worth it. But, it can still be cost effective, if it saves one service call.

The TSM will have complete troubleshooting steps, which it seems you will need to figure out the true cause of the issue. I will bet that your tractor has some non-factory wiring, which will complicate things.

 

Im a Power Engineer and Millwright with a fair amount of experience in electricity. The one I'm referring to is the middle on the left as I know that the 3 are tied together on the right and that comes directly from the battery. What I dont know is where the middle terminal on the left (load side of fuse) (which is missing) connects to where?

 

The fuse that protects that circuit is in place but the spade receptacle in the fuse box on the load side of the fuse (LEFT SIDE OF BOX) doesn't have a connection as it must have heated up and fallen out? I'm sure that's where my red wire came from. All I need to know is where the wire that is supposed to be there that is missing connects to?

 

So the fuse has a power supply from the right but isn't supplying anything as the terminal is missing along with the wire. Sorry if i didn't explain properly

 

And based on the wire that is no longer connected on either end, since I know it comes from the middle fuse left side and it’s only 10’ long, I believe it’s supposed to be connected to either the ign. Switch, PTO switch….

 

I believe it’s supposed to be connected to either the ign. Switch, PTO switch

That is what the schematic will tell you. I don't have a schematic for the X300, because it never gave me a problem that needed one. I do have one for the X500 series. There are a lot of similarities, but possibly some differences. There are at least six of them in the manual and they show different circuits with slight differences for different serial number ranges as they made changes.

On all of the ones that I saw, the middle fuse is for the accessory power port (what used to be called the cigarette lighter). The bottom one is for the starter solenoid circuit. The top one is for everything else, including the PTO. The bottom one with the blue wires is for the PTO also. The ECU has an output that has a blue wire on it, this controls the PTO relay. So I would check that the PTO relay is working correctly. They can fail. I would also check the diode across the PTO relay as those can also fail.

If you have an accessory outlet on your tractor, that is where the red wire is supposed to go. If you don't, the PO must have using it for something and might have made other changes to the wiring that you might need to trace/figure out. My X300 doesn't have a power outlet.

 

Really appreciate all of your help and will be contacting Deere again by phone for a proper wiring diagram..... I will update.... thamks

 

I doubt they will just give you one, but you never know. Usually, there is a lot of similarity between the models and while it is really nice to have a schematic it often isn't necessary for simple problems that are caused by a single failure. Complex problems and even simple ones that are caused by more than one thing are much harder to figure even if you have the schematic.

I had a similar situation with the radiator on my X749. It was leaking coolant. I couldn't tell from where exactly. I almost bought a new radiator before pulling it, because I didn't want to be without the machine for a few weeks. Since the radiator was leaking I pulled the radiator, but didn't buy the proper tools to really check it. I mean who wants to spend around $100 on the tools to test something that you KNOW is broken. Well I couldn't find the leak, by just looking. So I bought the pressure test kit. I hesitated before, because there are many choices and they include different number of adapter caps. I took a chance with the Mity-Vac one (for about $50). It has two small bayonet style ones (regular and deep). My radiator uses the small bayonet that is deep. There does not appear to be standard name for this size and the regular depth one is very close in size, but won't pressurize if it fits otherwise.

Even with the test kit, I couldn't tell for sure if it was leaking, because the inner tube I used leaked at the edges and then exploded getting me wet when I increased the pressure. So, I broke down and spent the $40 to get two radiator hose caps. With them, I was able to confirm that the radiator was NOT leaking. The leak was most likely from the lower radiator hose.

When I did an earlier inspection, I noticed there was a wear spot on the hose from the lower oil fill cap. I just hadn't gotten around to replacing the hose and coolant. Had I done that, I might have avoided having to remove and replace the radiator. At least now the radiator is very clean, since I pressure washed the exterior when I was checking it for leaks.

So, you are not alone in not wanting to spend money on things you might think you don't need, but probably do. At least I didn't spend $600+ on a new radiator I really don't need.