several points to make here. I am not defending the OEM, nor any government entity, just stating facts-and you can take it however you want.
First, understand that an ECU only knows voltage. That's all it knows. If you send 5v reference signal to a tps which is basically a glorified potentiometer, another wire sends a reduced variable voltage based on throttle position, back to the ecu. The ecu reads it and says "hey I'm at 1/4 throttle". All sensors are basically doing the same thing. A crank or cam sensor is a generator, the ecu reads the voltage and how that voltage is generated, then Sending a reading back to the ecu for the ecu to take the voltage and apply it. Therein lies a huge underestimation, or better term, misunderstanding. Just because you get a trouble code for a failed tps, doesn't necessarily mean the tps is dead; although the temptation is certainly there to just replace it with a new one. Oftentimes there are other reasons that the voltage that the ecu reads is high or low. Wiring! Grounds! Just to name two. You get the idea. How you test for those, is up to you. I do it one way y'all might do it another way.
What is the reason for efi? efi is electronic fuel injection. It can be gas or it can be diesel. It adjusts the injected fuel quantity and timing based on various sensors input to the ecu. The purpose is to provide a cleaner running engine, and the side effect of that is a smoother quieter running engine. That is why every single vehicle made nowadays is fuel injected, no more carburetors on anything but lawn mowers and some (few) outboard motors. It starts ice cold with no choke, no starting fluid, nothing. It starts hot. It idles good. And uses a little less fuel; assuming everything is working as designed and has not been 'modified'.
And therein lies huge issue(s). The systems as designed originally usually work mostly flawlessly. Consumers, however, have better ideas. They want more power. Simple. Don't we all? So aftermarket companies realized that consumers had wishes, and they made parts. These parts defeat the original purpose in order to make more power, and/or compensate for the elimination of certain features. But--in doing so, whether it be a simple power improvement, or compensation for the missing parts, now the engine emissions have changed. How? The original equipment as manufactured had to meet a certain emission standard, be it a noise emission, or chemical. When new, it met that. When modified, it doesn't. Usually.
So with that all in mind, if every Tom, Dick, and Harry that had an electronically controlled fuel injection 'equipment' (car/truck/tractor/mower/weed eater/etc) had access to the availability to change the fuel injection parameters, such that a 30hp tractor now can make 40hp with a simple stroke of a keyboard or click of the mouse, now you have the potential for a bunch of pieces of equipment to be modified outside of it's original parameters, affecting emissions. And reliability in a lot of cases. And with that, our government isn't too keen on that, nor is the original equipment manufacturer.
So that's why you are seeing the OEM's review this stuff, and that's also why they try to keep their software proprietary. Dealers need the software to make repairs, but most consumers don't need it-it's entirely possible to make changes that affect emissions, and if you don't know what you're doing, damage things beyond repair. If it's in warranty, that costs the manufacturer.
many think that kubota's efi stuff is just obd, and they'll have a code populated in their panel, and quickly google it. But keep in mind, that kubota's nomenclature is different than obd2 automotive stuff, and that's where confusion sets in. Trust me, been through it. Sometimes an automotive obd2 code has a certain meaning across the board, until you get to kubota and it may mean something similar but people find it from a youtube mechanic and automatically start fixing what the youtube tech said to, to find out that it wasn't the problem. Now you've spend hundreds or thousands of dollars and still have a problem. Or a worse problem. Of if you get real lucky, less of a problem.
oftentimes kubota (and other tractor manufacturers) will populate a trouble code and you can't clear it without the software and hardware. Pretty common in the trucking industry too. You can buy a code reader at the parts store for your car but it won't read all the codes, just some of them. And sometimes it won't even read it at all. They're very limited, and usually won't work with kubota or deere anyway.
Expense. Why's it cost so much to have a tractor worked on? Diagmaster (which I think is outdated now), kubota's software and hardware set, costs thousands and thousands of dollars. If you (a tech) use it 10 times a year and it's total cost is 10 grand, you have to justify $1,000 for each use just to pay for it. That doesn't include the 'license updates' that aren't free either. The actual numbers are examples only. The costs are high because they don't want consumers to use it. Also, the actual cost to dealers is high for a lot of reasons, one being that kubota doesn't really make it, they only supply it. In other words an outside company makes it, kubota gives them specs to make it to, so let's say Bosch makes it, they charge kubota $200 for it, then Kubota has to have programmers to license it, among many other things, and they're gonna have to pay the engineers to do their engineering...plus the workers at the warehouses, etc...now they have to put a price tag of $500 on it to break even, but they, like everyone else, is in the business to make money, so they're gonna put $750 on it and make $250 to cover other costs too (light bills, etc). You get the idea. And hopefully now you understand why things cost. It costs to make them, to send them, to stock them, and it even costs money to sell them. The more these costs increase, the more the consumer pays. Simple ain't it?
