While it is tied to the ECM, and requires specialized tools to recalibate or change, they are required to operate on the ODBII standard which means 3rd parties

While it is tied to the ECM, and requires specialized tools to recalibate or change, they are required to operate on the ODBII standard which means 3rd parties can and do create these tools (and aftermarket parts), it also means independent repair shops can and do make the repairs Here John Deere is not simply accused of making it more complex, but prohibiting any and all repairs not authorized by their own propriety computer software.