Another Battery Change, Another Dead ECU

[Art V]

The battery in my 2016 MX 5800 went dead last week, so I pulled it out and got it tested. It was bad so I bought a new one, installed it and got the crank, no start, p0605. Had the dealership come out and they couldn't get their laptop to communicate with the ecu, so they pick up the tractor yesterday and did some more checking.
Got the call yesterday afternoon, ecu is shot to the tune of $5000 parts and labor.
So I started researching and found this place and seems this a problem with kubota tractors and I haven't found anyone who can say why with a definitive answer. Or if this is going to happen again if the battery fails.
So, WHAT GIVES?

Shawn

 

[will721]

You didn't by chance test the charging system via battery disconnect while running did you?

 

[Art V]

You didn't by chance test the charging system via battery disconnect while running did you?

No, last time I used was a couple of weeks prior, I noticed the outriggers on the backhoe were bleeding off and I tried to start it to raise them up. I turned the key on, it went through the start up check cycle, tried to start it and nothing.

 

[GreensvilleJay]

Can I assume you have your old 'shot' ECU ?
If not ,get it back from the dealer ASAP ! If they try to give you ANY 'BS', contact local cops and lay fraud charges, 'theft over $xxxx', or whatever is the applicable laws in your area.
I'd also get email Kubota Japan and get them to return your $5000. Check owner's manual for 'how to change battery' procedure,be interesting to see what's WRITTEN ( if anything.....)

BTW there is NO way a simple battery change should or could cause an ECU to 'fry'. MILLIONS of batteries are installed every year either ON THE ASSEMBLY line , or at dealers or roadside or garages and you don't hear about this happening......

 

[jaxs]

It's above my pay grade so I could easily tell you more than I understand about it. Here's what has been found on some other vehicles. In a nutshell short circuit while r&r battery. Anything with electronics requires one or more capacitors. After battery cables are disconnected there's enough power stored in some systems to do damage when cables touch chassis. To play it safe,carfully insulate cable ends or suspend to prevent short until system has time to bleed stored energy. It cost about 10 cents to prevent it at time of manufacture but some companies don't and reap income selling replacements. Pretty slick money generator for mfgr don't you think? Hang on to the old parts. There's people capable of rebuilding it with a few dollars in parts. I first was told about it by a retired Isuzu parts distributor that hooked up with an electronics technician black marketing rebuilt electronics. Dealers beat their door down buying parts fat deep discount over what they had to pay for mfgr distributed parts.

 

[Lil Foot]

Former neighbor in the high country changed the battery in his JD. (don't know the model)
He momentarily reversed the plus & minus cables, fried the CPU.
$1800 if I remember correctly.

 

[GrizBota]

I suspect tech didn’t know how to hook their computer up to the tractor and solved a nonexistent problem with your money. Pretty normal for parts swapers to start with the most expensive part if someone else is paying.

 

[Art V]

Can I assume you have your old 'shot' ECU ?
If not ,get it back from the dealer ASAP ! If they try to give you ANY 'BS', contact local cops and lay fraud charges, 'theft over $xxxx', or whatever is the applicable laws in your area.
I'd also get email Kubota Japan and get them to return your $5000. Check owner's manual for 'how to change battery' procedure,be interesting to see what's WRITTEN ( if anything.....)

BTW there is NO way a simple battery change should or could cause an ECU to 'fry'. MILLIONS of batteries are installed every year either ON THE ASSEMBLY line , or at dealers or roadside or garages and you don't hear about this happening......

No, tractor is still at the dealership. I am going to talk to them tomorrow. Also calling Kubota.
Could hooking up a battery tender(no reverse polarity) have caused this? Dealer said no. There was no arching when changing battery and I protected cables when they were removed.
Is it possible if the voltage was low enough for long enough, that it lost its memory or something along those lines?

 

[Art V]

I suspect tech didn’t know how to hook their computer up to the tractor and solved a nonexistent problem with your money. Pretty normal for parts swapers to start with the most expensive part if someone else is paying.

I am going tomorrow to dig a little deeper into what all they did to come to their conclusion. My thinking is there might be other reasons why the laptop wouldn't communicate with it, wiring issue, etc.

 

[Art V]

Another question, the bracket the ecu is mounted on is loose enough that I can move it up & down at least 2". Could that thing flopping around cause this failure and the battery issue just be a coincidence?

 

[GreensvilleJay]

really the ECU wasn't mounted solidly ??? Sounds like 'tech' didn't do the install properly....
THAT could explain failure IF they rely upon the case to be the ground( which is really, really STUPID....)
'Communications' SNAFU is common, too common with CANbus.... one of the worst 'engineered' systems ever...a MARGINALLY 'out of spec' wire will stop ECU communicating to PC.

'low battery ' won't affect 'memory', well shouldn't as all micros today have internal hardware to deal with that,have for decades....I'll presume they have some form of POST Power On Self test, similar to what PCs have had from the 70s. Should also have 'checksum'testing of stored data like calibration numbers to confirm the 'numbers' are correct.
With over 5 decades in the industry, 2 designing 'hot swap' systems, I get really, really pizzed when I hear about 'fried ECU and owners on the hook'. It's100% preventable. and NOT the owner's fault !!!

 

[Art V]

really the ECU wasn't mounted solidly ??? Sounds like 'tech' didn't do the install properly....
THAT could explain failure IF they rely upon the case to be the ground( which is really, really STUPID....)
'Communications' SNAFU is common, too common with CANbus.... one of the worst 'engineered' systems ever...a MARGINALLY 'out of spec' wire will stop ECU communicating to PC.

'low battery ' won't affect 'memory', well shouldn't as all micros today have internal hardware to deal with that,have for decades....I'll presume they have some form of POST Power On Self test, similar to what PCs have had from the 70s. Should also have 'checksum'testing of stored data like calibration numbers to confirm the 'numbers' are correct.
With over 5 decades in the industry, 2 designing 'hot swap' systems, I get really, really pizzed when I hear about 'fried ECU and owners on the hook'. It's100% preventable. and NOT the owner's fault !!!

The bracket has rubber bushings around the mounting bolts to absorb vibration I would think, but it had to be flopping up and pretty violently when going over any rough terrain( never happens on a tractor, right?) and as far as tech not doing install properly, I have a backhoe on this and had a leak recently, pulled the cover off the valve bank and not one of the hoses were tight( at least 3/4 turn, the one leaking 2 1/2 turns) so initial set up is definitely in question.
Correction it is the bracket for the ecm that is loose.

 

[The Evil Twin]

Highly doubtful that a loose mount caused this. My MX bike goes through a lot worse than your tractor. Roadrace bike does also. Hell, the ECU came out of the race bike in a crash one time. Found it, dusted it off and it's still in there today.

 

[RCW]

Jeepers - this kind of thing makes me hesitant to replace batteries in our vehicles. Something I’ve done for decades without concern…

 

[TheOldHokie]

Something I’ve done for decades without concern…

You and a few million others. I have had the battery on my L3901 out twice in the first three years of ownership..
..

Dan

 

[fried1765]

Jeepers - this kind of thing makes me hesitant to replace batteries in our vehicles. Something I’ve done for decades without concern…

FWIW: Removing the battery on a late model Mercedes is reportedly bad news.
Apparently requires a tow to the the rip off dealer(+ labor at $205 per hr.) for a computer reset.

 

[TheOldHokie]

FWIW: Removing the battery on a late model Mercedes is reportedly bad news.
Apparently requires a tow to the the rip off dealer(+ labor at $205 per hr.) for a computer reset.

But not a new ECU. That's just plain old owner unfriendly coding.

Dan

 

[GrizBota]

But not a new ECU. That's just plain old owner unfriendly coding.

Dan

Plain old self serving design to maximize profit at the expense of the user. And there’s more of it everyday.

Unfortunately most folks don’t know enough to know they are getting screwed. In the case of Mercedes, most uses probably won’t care if they knew, other than the inconvenience. I suspect Mercedes recommends replacing the battery proactively at a specific timeframe interval as routine maintenance. Plus, more money to the dealer. Funny how that works.

 

[Runs With Scissors]

If not ,get it back from the dealer ASAP !

Here in Michigan, a "vehicle repair facility" does not have to give "certain parts" back, but only have to give you a chance to "inspect it".

I don't recall if ECU's or PCM's count or not.

I'm not sure if that applies to tractors, but I bet it's similar.

 

[cthomas]

Some of the late model Mercedes had 2 batteries, the primary and a auxiliary battery to prevent issues. Just still had to be careful to not all the positive cable touch the body. I use a bungee cord from the positive to the hood latch. Also they do make(I do use) an ALDL(OBD2 port)connector that supplies power/ground to the computer for vehicles that have issues(Think high end vehicles). A buddy changed the battery on a BMW with the door open and fried the driver door module that was a $1200 mistake.