Is it the ECU (computer)

[sailingsolo]

2018 L47TLB with about 500 hours stopped while I was driving it. Saw an Engine Stop alarm. Was able to immediately restart the tractor and continued using it. The tractor was scheduled for the dealer before this happened so told them about the alarm. The dealer thought the problem to be with the fuel-stop solenoid so they replaced it.

After I got the tractor back I used it but a few minutes and it stopped again. Searched through the menu and found the same three alarms that I had seen on the initial tractor stopping but this time the console did not show an Engine Stop alarm. Had the dealer take the tractor to the shop and this time the dealer could not find/see the alarms. They tried a couple of tricks with the tractor to create an alarm and couldn't.

The solenoid the dealer replaced proved to be good and didn't need to be replaced. However, they were unable to find any problem. Because of the electrical alarms issues not always showing I believe the problem to be with the computer. Alarms do not clear themselves, however, by cycling power the problem disappeared. Comparable to rebooting the home computer.

Tractor stoppings are not normal. Alarms disappearing by themselves are not normal. The computer is too expensive to replace because it might be the problem. Will wait and see if the computer is the problem.

I might not be right but it does give you something to think about.

 

[Roadworthy]

See if the dealer has the capability to reprogram or update the program in your computer. There could have been firmware or software updates since your tractor was manufactured. It's also possible your software has a glitch this would overwrite.

 

[ericm979]

It's much more likely to be a bad sensor. Parts that integrate with the physical world are much less reliable than purely electronic parts. The computer may be clearing the errors on reboot because that's what it is programmed to do.

Software is of course all garbage. But blindly replacing it is a cargo cult approach to the problem.

You should write down the alarm messages next time, and look in the shop manual to see if the troubleshooting section has any answers for them.

 

[bearthebruce]

The alarm codes (diagnostic trouble codes) should give a clue as to what is going on. With the codes, look at the wiring diagram to see what might be in common. For instance, maybe the codes point at 3 sensors. If so, then look for a common ground or a common supply (+12) point. Perhaps a wire has come loose causing the sensors to malfunction.

Rarely is the root cause the most expensive part in the system - the ECU.

 

[Oaktree]

Are you doing anything in particular when it dies? Not sure what those "tricks" the dealer tried to re-create the problem, but for a problem that happens as quickly as it does for you they should be able to re-create it. I'm sure it's possible that whatever's failing doesn't set any codes, but I get the impression they've had it in the shop a couple times.
At this point I question the competence of their service dept.

 

[sailingsolo]

Thanks for the replies. Dealer had the codes when they "fixed" it the first time. 606, 627, and 629 which take you to the fuel system and that is why they they replaced the fuel stop solenoid. Same code numbers showed on the console when it stopped the second time. They didn't show when the dealer checked the computer or the console.

The trick the dealer tried was to purposely put it against something and stall the tractor, hoping then an error might show. It Didn't.

I do not have any manuals to troubleshoot with and uncertain what the dealer has. Talked with the service manager and he is uncertain what the code numbers directly refer to. Seems they steer you in the direction but don't state what actually caused the problem. So it becomes a peck and hope. As we used to say at work, "Swap 'til you drop."

If the tractor stops because I am driving it the obvious solution seems to be don't drive it.

 

[IndyJay]

If the tractor stops because I am driving it the obvious solution seems to be don't drive it.

"Doctor, it hurts when I do this..."

Sounds like they made the simplest, easiest, cheapest guess related to "fuel system".

 

[ericm979]

Googling the error codes and the vehicle can often turn up interesting information. (and often garbage as well).

This is an interesting discussion: Codes popped up any help

 

[mikester]

I'd start with bad battery contacts, bad grounds, bad wire harness connections. Disassemble, clean, coat with dielectric grease and reassemble.

Look out for insulator issues causing intermittent grounds. Joys of electrical systems. Get an electrical schematic and trace your wires.

You need to be persistent and methodical. Swapping random parts is an expensive way to not fix the problem.

 

[finn1]

Sounds like a wiring harness issue.
It would be highly unlikely that an intermittent fault would be a sensor Ecuador’s fault.

Wiring harness or plug / pin issues are often intermittent.