You need electronics and computers for cost-effective compliance with emissions requirements. Emissions limits have been one of the most positive government policies in my lifetime, saving millions of QALYs.
There's lots of other electronics in most modern vehicles, but the public manufacturer rationales for electronic lockdowns almost always point back to emissions concerns because they're so defensible. How do you separate them?
These are regulations, not laws, and can be changed fairly easily. E.g the EPA recently changed the rules requiring NOx sensors and power downs, which were the most failure prone components of the system, while still mandating the actual equipment that scrubs NOx.
There's no particular reason why a mechanical device needs computers for emissions, as the emissions removing components can still be attached and managed via simpler means. All emissions removing components are effectively physical devices, whether you are talking about carbon filters or PCV valves or particulate filters or the urea fluids that are added to the fuel. None of them requires complex software in order to function. There is no reason why you need to buy an official John Deere branded emissions component that is software locked to tractor and costs 10x the price of third party components that do the same thing.
Also, there is a large room to maneuver between "I want a sensor with some circuitry in it" and "the entire tractor is a proprietary computer with locked down parts". The right to repair movement is not about removing tech, but removing unnecessary proprietary tech that is designed to prevent owners of devices from repairing those devices themselves or with third party components.
defeat devices aren't even complicated (they just fake the sensor data to ECU to get what owner needs). Locking down is pointless. Most people are not tuning their cars.
IF we wanted to do it properly, I'd imagine we'd have zero mandatory locks on ECU, just a little closed down black box with sensor installed in relatively tamper-proof way (of course there will always be one, the target is for 90% of people to not bother), logging away and maybe sending check engine light if it detects wrong AFR for too long.
Then you just check that on yearly MOT + any signs of tampering. Then owner is free to tune the engine as they want, provided the exhaust is still within the norms for most of the time.
> How do you separate them?
Mandate common interfaces and open hardware. I shouldn't have to buy a $10k dongle to sniff codes. I certainly shouldn't have to buy a different one for each manufacturer.
How do you define "electronics" and "computers"? Is a general-purpose computer running Java in the same category as a microcontroller running a tight loop with lookup tables for fuel and spark?
Perhaps this is naive, but I would imagine that farm equipment is a rounding error in terms of global emissions. Compare the number of tractors to the number of trucks...
I would have expected policy to be pragmatic here, with (relatively) relaxed emissions requirements, since an affordable and reliable food supply is in the national interest? Sounds like that's not the case