# Tym T353 HST dies suddenly but starts right up again



## RustyCannon (Jun 6, 2018)

My TYM T353 HST has just short of 500 hours on it. It has the Mitsubishi S4L2 engine.

While operating it, the engine will just shut off suddenly. It will then start right back up. It would do this about every 3-4 hours, usually when I was working it clearing snow or grading our road. I suspected the seat safety switch. Now the problem has started happening every few minutes while operating the tractor, so the thing has become useless. Still suspecting the seat switch, I bypassed it. That isn't the problem, as the engine continues to die suddenly when it is at operating temperature. 

I can hear the clack from the fuel solenoid when it happens. Sometimes, when the tractor is idling, the "Check" light will come on and go off, but in monitoring the dash while operating the tractor, there are no warning lights or indications that anything is wrong prior to hearing the fuel solenoid clack and the engine dying.

The only thing I've been able to find on the "Check" light is that it indicates an unsafe condition, but it doesn't outline what an unsafe condition is.

Any ideas?


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## RC Wells (Dec 26, 2008)

I suspect you have triggered the error by bypassing the seat switch. Remove the bypass and change your fuel and air filters. If that does not solve the problem have it scanned by the dealer.

I believe that is a tier 4 engine, so scanning for error codes will save a lot of grief.


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## RustyCannon (Jun 6, 2018)

RC Wells said:


> I suspect you have triggered the error by bypassing the seat switch. Remove the bypass and change your fuel and air filters. If that does not solve the problem have it scanned by the dealer.
> 
> I believe that is a tier 4 engine, so scanning for error codes will save a lot of grief.


Thanks for your response! Yes, putting a permanent "closed" on the seat switch did nothing to affect the symptoms, so that will be put back to normal. 

The dealer is 100 miles away and I have no way to get it in. They did respond to my email this morning. The service manager suspects an oil pressure switch and said that low viscosity oil might cause the trouble. I'll ask him about scanning for errors. Thanks for that suggestion. 

I'm unclear as to how the fuel filter or air filter would cause the fuel shut-off solenoid to activate. Are there some safety circuits monitoring air and fuel flow?


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## RC Wells (Dec 26, 2008)

If that has the Bosch licensed hybrid injection pump, fuel restrictions can cause it to overheat and shut down. A few times and the pump will need to be repaired. The Tyms I have seen come with an Asian copy of the Bosch VP44 hybrid injection pump.


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## RustyCannon (Jun 6, 2018)

RC Wells said:


> If that has the Bosch licensed hybrid injection pump, fuel restrictions can cause it to overheat and shut down. A few times and the pump will need to be repaired. The Tyms I have seen come with an Asian copy of the Bosch VP44 hybrid injection pump.


Thanks for that tip. I'll take a look at it. I know that the engine is a Mitsubishi S4L2. I have the manual for the engine.

The air cleaner elements looked clean. It could use an oil change, so that is #1 on the list when I get a chance to work on it. The fuel filter is on the list too. Thanks again for your help and I'll report back when I've solved the problem or have more information.


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## RustyCannon (Jun 6, 2018)

RC Wells said:


> If that has the Bosch licensed hybrid injection pump, fuel restrictions can cause it to overheat and shut down. A few times and the pump will need to be repaired. The Tyms I have seen come with an Asian copy of the Bosch VP44 hybrid injection pump.


Just FYI. I have a PDF copy of the manual for the S4L2 engine and it shows that the injector pump is a Bosch M type.


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## RC Wells (Dec 26, 2008)

Your in luck, the M pump series are quite durable. Likely just a filter issue.


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## RustyCannon (Jun 6, 2018)

RC Wells said:


> Your in luck, the M pump series are quite durable. Likely just a filter issue.


Thanks. I'll be changing the fuel filter. Just ordered the oil pressure switch from the dealer. Their next best guess is the solenoid itself. I'm scared to ask the price of that.


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## RC Wells (Dec 26, 2008)

The solenoid is easy to test with a multimeter. Once the tractor shuts down, leave the key alone with someone in the seat, then check the voltage to the solenoid. If it is at least 12.5 then you know there is still power to the solenoid circuit. Then switch to ohms and check the solenoid, if it is good the reading will be infinity. If it is bad there will be some value displayed.

If the solenoid is good, and you have power to it, the problem will be fuel related. Your repair manual will show if the tractor has a fuel transfer pump (also known as a lift pump). Most are electric now days, and if it is make sure that is running when the key is on.

But, first make sure the fuel filter(s) are good. With today's diesel those filters must be changed every hundred hours, if not sooner.


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## RustyCannon (Jun 6, 2018)

RC Wells said:


> The solenoid is easy to test with a multimeter. Once the tractor shuts down, leave the key alone with someone in the seat, then check the voltage to the solenoid. If it is at least 12.5 then you know there is still power to the solenoid circuit. Then switch to ohms and check the solenoid, if it is good the reading will be infinity. If it is bad there will be some value displayed.
> 
> If the solenoid is good, and you have power to it, the problem will be fuel related. Your repair manual will show if the tractor has a fuel transfer pump (also known as a lift pump). Most are electric now days, and if it is make sure that is running when the key is on.
> 
> But, first make sure the fuel filter(s) are good. With today's diesel those filters must be changed every hundred hours, if not sooner.



Thanks once again. Great information!


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## RustyCannon (Jun 6, 2018)

Just to update y'all. I changed the oil pressure sw, changed the oil and filter and changed the fuel filter. Took it out with the box scraper on to clean-up some erosion in my driveway. Ran it for 20-30 minutes and *clack*, it shut down. Started it back up, tried to move it and it shut down again. Tried once more. Same thing. Let it sit for a couple hours to cool down. Started it up and backed it about 60 feet into the garage. 

I ran across someone with a similar problem, same model tractor, and he cured his problem changing the fuel shut off solenoid. I'm ready to try that. If that doesn't fix it, I'll need to figure out how to get it to the dealer, 100 miles away.


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## RustyCannon (Jun 6, 2018)

RC Wells said:


> The solenoid is easy to test with a multimeter. Once the tractor shuts down, leave the key alone with someone in the seat, then check the voltage to the solenoid. If it is at least 12.5 then you know there is still power to the solenoid circuit. Then switch to ohms and check the solenoid, if it is good the reading will be infinity. If it is bad there will be some value displayed.
> 
> If the solenoid is good, and you have power to it, the problem will be fuel related. Your repair manual will show if the tractor has a fuel transfer pump (also known as a lift pump). Most are electric now days, and if it is make sure that is running when the key is on.
> 
> But, first make sure the fuel filter(s) are good. With today's diesel those filters must be changed every hundred hours, if not sooner.


Sounds easy enough except that I'm alone. No one to help.


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## Guest (Jul 30, 2018)

You might need to buy or make alligator clip leads/adapters for your multimeter so that 2 hands are enough?


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## RustyCannon (Jun 6, 2018)

Graysonr said:


> You might need to buy or make alligator clip leads/adapters for your multimeter so that 2 hands are enough?


Got 'me. However, this solenoid is hardwired with a pigtail that goes to an enclosed connector. To get an electrical connection, I'd have to bare some wire. I don't like cutting into insulation.

I checked with the dealer and a new solenoid from TYM, including shipping and drop-ship charges runs around $250. The solenoid is an extremely common part available from dozens of sellers from WalMart to Amazon to several sellers on ebay. Makes me think they're a common point of failure. They run $38-$58 on-line, shipping included. I've ordered one. I'll swap it out and report if anything changes or not. 

Next step is to pay to haul the thing to the dealer and pay the big bucks to have them figure it out. I wish I had more time to dedicate to troubleshooting it, but I just don't.


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## Guest (Jul 30, 2018)

Yes in in end you can only do what you can do.


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## RustyCannon (Jun 6, 2018)

I ordered a new shut off solenoid. Got it Friday. Saturday morning, I removed the old one and attempted to install the new one but there is a machining error with the threads and it simply wouldn't go more than a quarter turn. 

I took the nut off the old one and put it on the new one and it went on but was very hard to turn. 

Took the nut off the new one and put it on the old one and it went right on, as it should.

So, I've ordered another one, I'm returning this one and maybe next weekend I'll get to try this again.

In searching for the part number for the solenoid, I found some good reference material.

*Engine service manual from TYM with Mitsubishi S4L and S4L2:*
http://tym-mitsubishi.ru/booklets/Mitsubishi SL series ServiceManual.pdf

*Parts Catalog for Tym T303/T353NH and HST 
https://static1.squarespace.com/sta...1adda9a1d015/1483141153350/T303+T353+NHEU.pdf

*


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## RustyCannon (Jun 6, 2018)

Just to catch up on this. The first solenoid I ordered took a week to get but the threads were defective and it wouldn't install. Returned it for refund and simultaneously ordered another new one. Took a week for that one to get here and when I unboxed it, there was greasy dirt in the threads as though someone had tried it and returned it for some reason. May have been just fine, but I decided to return that one without trying it. I ordered a third one and receive that one Thursday afternoon. Installed it Friday morning, but didn't have time to test the tractor. 

I had a couple hours clear this afternoon, so I started it up and after a short warm-up, I started using it to take some erosion out of my driveway. Ran for about 15 minutes or so and *clunk* & shut down. I waited about 30 seconds and started it back up. My scraper blade was still down, so I pushed some road base backwards about 70 feet and it shut down again. I started it back up, raised the blade, and backed it another 100 feet or so into the garage where it sits. 

The Check light started coming on intermittently after I had the tractor warmed up and working. It comes on and goes right back off but this hint must be something to do with what is shutting the solenoid off. Oil pressure switch is new, fresh oil and filter are installed. The troubleshooting sections in the operator and shop manuals have nothing about this trouble. 

I'm frustrated beyond words at this point. According to the book, there are several switches that can open that circuit to cause that shut-off solenoid to shut the engine down. The two I first suspected - the seat switch and the engine oil pressure switch did not fix the problem. The engine temp has a gauge and the engine is running nice and cool according to the gauge.


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## RustyCannon (Jun 6, 2018)

This tractor is a 2007 TYM T353 HST. Does anyone know what conditions can cause the "Check" light to come on while the tractor is being operated?


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## BigT (Sep 15, 2014)

Hi Rusty,
Call your dealer and ask him what the check engine light may indicate. My thought on this is that your fuel supply may be marginal. It runs till it is out of fuel, but after a brief shut down the fuel replenishes somewhat and it can go again for a brief while and shut down again. If a diesel quits running usually it is not getting fuel. I would check the outlet of your fuel tank for an obstruction (piece of dirt) blocking flow. Check the fuel line/flow at the inlet to the filter. Check fuel flow at the inlet to the injection pump. It must be more than a trickle flow.

Another check to make if you can.....immediately check for voltage/power at the fuel shut-off solenoid when it quits running.


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## RustyCannon (Jun 6, 2018)

Thanks for the suggestions. I have an email off to the dealer asking what the Check light can indicate, since the books don't really have that information. The fuel flow is fine until the fuel shut-off solenoid shuts it off. I've verified that and the fuel filter is fresh. The key is going to be what causes that solenoid to shut off. It's likely going to be a loose ground or a bad switch in that circuit.


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## BigT (Sep 15, 2014)

There may be a relay providing power to the shut off solenoid?? Some tractors have a relay to provide higher power for the solenoid to "pull in" and then a lesser power to "hold" that position.


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## RustyCannon (Jun 6, 2018)

Thanks, BigT. That's a distinct possibility but the schematics are horrible. I'm hoping for some direction from the dealer. Wish I had more time to devote to this project but I have another major project that is taking precedence.


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## EdF (Sep 15, 2014)

Dumb question....have you checked the fuel tank vent or the fuel cap vent for plugging? The symptoms seem to fit a vacuum buildup in the tank.


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## thepumpguysc (Jan 25, 2015)

I sure hope you find the problem as its a REOCCURING theme w these smaller tractors.
Looking around the web theres hundreds of complaints.. weather its a Mitsub. engine or a Kubota engine.. & it doesn't matter WHO made the tractor..
It usually ends up being, either a relay{hidden}& theres usually 3, a start{pull}, a run{hold} & a timer.. & they're all hidden.. OR the sol. is bad.. OR the key switch is bad{unlikely} OR a safety switch..
If you figure it out..PLEASE post the findings.


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## RustyCannon (Jun 6, 2018)

EdF said:


> Dumb question....have you checked the fuel tank vent or the fuel cap vent for plugging? The symptoms seem to fit a vacuum buildup in the tank.


Not a dumb question at all, EdF. In fact, I had that happen to my lawn tractor. It would run for about an hour and then appear to run out of gas. Thought I had a clogged fuel filter. Changed it, filled the tank and same thing. Fuel pump? Changed it. Same thing. The light in my head came on when I heard the pshshshsh upon unscrewing the gas cap. Yep. Clogged solid. Cleaned out the gas cap vent and no more problems.

When the TYM started shutting down, I thought about that experience and checked the fuel cap and cleaned the vent, but it didn't help. Consulted my brother (retired heavy equipment mechanic) and he suggested the same thing.

But the symptoms aren't like an engine running out of fuel (diesels, in my limited experience, act like gas engines when starving for fuel - they sputter and try to keep running, but then die.)

Then I started listening closer and I could clearly hear the "clack" of the solenoid that closes the fuel off at the injectors. *The engine stops quickly as though turned off by the ignition key. *


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## RustyCannon (Jun 6, 2018)

*I think I've solved the problem*, and I feel pretty stupid about what I found.

More and more, the symptoms kept pointing to an overheated transmission. But why would the transmission overheat when the engine wasn't? It's probably due for an oil change, but certainly not critically overdue. So I had resigned myself to having the tractor hauled to the dealer, 100 miles one-way. I don't like asking mechanics to work on dirty equipment, so I decided to clean it up yesterday and get it ready for the pros. 

While washing the dust off engine, I noticed something that I'd never noticed before. In front of the engine radiator, behind the transmission oil cooler, there is a screen. The screen fits tight against the front of the engine radiator and is painted black just like that radiator. The transmission oil cooler is a natural aluminum color and there is a small air gap between the two. The oil radiator was clean, save for a tiny amount of dust. 

But that screen was clogged. It looked like a clothes drier lint filter after the first drying of new towels. The screen lifts out easily. I cleaned it off and replaced it. I finished giving the tractor a bath and let it drip dry for a couple hours. 

Then I went out and started it up, and started working it. I ran it for over an hour grooming erosion out of my driveway and I had no problem. Recent attempts to work the tractor have only lasted about 15 minutes or so - just long enough for the transmission to get up to working temperature (or so I theorized - I've never seen any idiot lights warning of high trans oil temp.) I haven't been able to get more than 15-20 minutes work out of it for last several times that I've attempted, so working without shutting down for over an hour leads me to think the problem is solved.

I don't know why the engine wasn't running hot. According to the engine temp gauge, it was normal. Even though the oil cooler was unobstructed, there would have been little airflow through it because the fan wasn't able to draw air through the engine radiator. 

If this was the problem, I'm very disappointed that there was no transmission overheat idiot light indication. A hint like that would have been very valuable. Now I want a temp gauge for the transmission.


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## RustyCannon (Jun 6, 2018)

*I still have the problem.*

Had a chance to work the tractor for 75-90 minutes doing road maintenance and it shut down, same symptoms. The fact that it now runs longer since I cleaned the radiators (it was shutting down after 15-20 minutes of work prior to that,) leads me to believe that I'm on the right track - that the transmission must be overheating. How that message gets to the engine shut-off solenoid is still a mystery. 

I have a PTO seal on order and when that arrives, I'll be taking the tractor to my local tractor repair guy and will ask him to flush and bleed the transmission, put a new filter on it, and do any other diagnostics that can be done.


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## RustyCannon (Jun 6, 2018)

*The latest on this trouble..*.

I'm in the middle of a kitchen and bath remodel that is taking months, so I have no hours to spend troubleshooting this, so I took it to a local independent tractor repair guy. The tractor needed service anyhow, so I had him bleed and change the hydraulic fluid and filter. He did all this work for less than what it would have cost me to have the tractor hauled the 200 mile round trip to the dealer and back.

My most recent experiences had led me to believe that the trouble was heat related, but in taking it off the trailer, cold, at the repair garage, it died twice on me. The mechanic said that it died four times on him when he was moving from outside to inside the garage. 

He chased down the electrical problem. He was able to tap into a wire for the fuel shut-off solenoid's hold coil. He attached a 12V light to that and he said it was flickering all the time, but occasionally would flicker off for a longer period and that is when the solenoid would deactivate, killing the engine. 

He traced that back to a module under the dash (on the fuel gauge/temp side). He said he could duplicate the trouble be pressing on the module. He said he could not duplicate the trouble by stressing any of the wires or connectors going into the module. I assume the module was sealed, but I failed to ask him that.

He rigged a wire around the module to provide power to the solenoid whenever the tractor is running, essentially bypassing all the safety switches, but allowing the tractor to run dependably. 

The electrical documentation is so poor, I really have no idea what part to ask the dealer for to replace the module, but to be honest, I haven't taken the time to call the dealer on it and I'm a bit scared of what the price might be.

I found one schematic diagram that had a "controller" shown, but now I can't find that schematic. The shop manual does a great job telling you in deatail how the fuel gauge works (just like they have for decades), but has nearly zero mention of this safety shutoff system. 

So that's where I am for the time being. The tractor works and that's the most important thing to me. I'd like to have all the safety protections working too, but it will probably be spring before I'll have time to play with it.


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## thepumpguysc (Jan 25, 2015)

Its just a relay.. a plug-in.. it should have the part # on it..
Its the same problem over & over.. The solution is> replace the relay..
BUT.. nobody will post a pic of these hidden friggin relays.!!!
Its EASY to tell people, its a "relay" problem.. BUT.. the next question is> wheres the relay??


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## RustyCannon (Jun 6, 2018)

thepumpguysc said:


> Its just a relay.. a plug-in.. it should have the part # on it..
> Its the same problem over & over.. The solution is> replace the relay..
> BUT.. nobody will post a pic of these hidden friggin relays.!!!
> Its EASY to tell people, its a "relay" problem.. BUT.. the next question is> wheres the relay??


You're right, of course. Had I done the work myself, I'd have taken pictures of the module, showing its location and where the jumper was applied to bypass it. Hopefully it will have a part number on it, but my fuel shut-off relay didn't. It had been painted-over, apparently in the engine build. 

My mechanic described the module as being mounted behind the instrument panel on the right side (curb side, passenger side, the side of the instrument panel that has the fuel gauge, temp gauge, and ignition switch.)

When I have the time to open it up, I _will _post pictures and the part number if it can be found.

It is highly disappointing that TYM doesn't provide any documentation that would show the location of this relay and cross-reference it to a part number.


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## thepumpguysc (Jan 25, 2015)

I know whatcha mean.. especially when its such a common problem..


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## FLA45fan (Aug 9, 2010)

I'm watching this thread . . . My 2008 TYM 353HST does the same thing. My dealer went out of business a year after I bought mine. Currently I have about 225 hours (yeah, ultra low use!) on it mostly for beach cleaning and snow removal. I'm located in Western NY.
More later . . .


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## RustyCannon (Jun 6, 2018)

FLA45fan said:


> I'm watching this thread . . . My 2008 TYM 353HST does the same thing. My dealer went out of business a year after I bought mine. Currently I have about 225 hours (yeah, ultra low use!) on it mostly for beach cleaning and snow removal. I'm located in Western NY.
> More later . . .


I feel terrible that I haven't had the time to dig into this further to find and photograph the offending module. I don't see any time soon that I will have the time, but who knows, maybe some time this summer. My apologies to all who are following this thread. I promise that I haven't forgotten about it.


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## Michael Bardin (Jun 24, 2019)

RustyCannon said:


> I feel terrible that I haven't had the time to dig into this further to find and photograph the offending module. I don't see any time soon that I will have the time, but who knows, maybe some time this summer. My apologies to all who are following this thread. I promise that I haven't forgotten about it.


I to have a 2008 353HST with the same problem, I have narrowed it down to one of the three relays located behind the instrument panel. I found replacement relays by using the part number thru Amazon. The relays can be purchased for $19.00 each. You can remove the top half of the dash panel very easily by removing the rubber grip on the throttle lever, one bolt center behind the steering wheel, one each side, and two at the top of the fire wall just under the hood. Will post later if this cures the issue.


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## Michael Bardin (Jun 24, 2019)

2008 353HST update, replaced the three relays located behind the instrument panel, have worked the tractor for two days, approximately 6 hours each day without any problem. The check light is off for most of that time. At times the check light will come on but no shut down so far, I have no idea what is going on with the check light.


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## RustyCannon (Jun 6, 2018)

My check light used to come on also. It seemed random and didn't necessarily coincide with the engine shutting down. I don't recall seeing it since the work-around that my mechanic did for me.

Do you have pictures of the relays you replaced?


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## Clyde#1 (Feb 14, 2021)

RustyCannon said:


> My TYM T353 HST has just short of 500 hours on it. It has the Mitsubishi S4L2 engine.
> 
> While operating it, the engine will just shut off suddenly. It will then start right back up. It would do this about every 3-4 hours, usually when I was working it clearing snow or grading our road. I suspected the seat safety switch. Now the problem has started happening every few minutes while operating the tractor, so the thing has become useless. Still suspecting the seat switch, I bypassed it. That isn't the problem, as the engine continues to die suddenly when it is at operating temperature.
> 
> ...


My 2010 TYM is doing the same thing. After changing ignition witches, fuel solenoids cleaning all wiring the problem persisted. With a friends help I rigged a light to the 12 volt wire on the solenoid behind the injection pump. When the light was on the tractor ran= light goes out tractor stops. Next I ran a Hotwire from the battery to the solenoid and light. The light came on , the Solonoid opened and the tractor runs without stopping. Disconnect the hot wire and the tractor stops. So that keeps the tractor running but are you damaging any other systems? After talking to a experienced dealer he said after the solenoid opens the voltage to it is reduced normally. I am working on a way to do this to prevent any other damage to systems. Hopefully this will keep the machine going. Sounds hoaky but a cheap easy fix. My machine is a 2010 with 1000 hrs. Good luck!


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