Ok, first I learned a nice $5000 used tractor is more likely a $10000 one

   / Ok, first I learned a nice $5000 used tractor is more likely a $10000 one #31  
Here is the history of the OBD according to wikipedia. GM was an early adopter of a version of the concept. VW actually used the first computer in an auto. It was first instituted and later mandated in California. The US soon followed. For all the grief we give to California, we soon grow to appreciate the changes that they force upon the rest of us but at first they seem crazy. Still do. The reason the tractor industry is behind on adopting the technology is likely because resistance was higher. Still is. I guess the good news is that we get to benefit from all the knowledge gained by the auto industry. I'm just hoping I don't regret buying new later on.

History[edit]
1968: Volkswagen introduces the first on-board computer system with scanning capability, in their fuel-injected Type 3 models.
1978: Datsun 280Z On-board computers begin appearing on consumer vehicles, largely motivated by their need for real-time tuning of fuel injection systems. Simple OBD implementations appear, though there is no standardization in what is monitored or how it is reported.
1980: General Motors implements a proprietary interface and protocol for testing of the Engine Control Module (ECM) on the vehicle assembly line. The 'assembly line diagnostic link' (ALDL) protocol broadcasts at 160 bit/s. Implemented on California vehicles for the 1980 model year, and the rest of the United States in 1981. Most owners can read DTCs (Diagnostic Trouble Code(s)) by commanding the ECM (Engine Control Module) to flash the CEL (Check Engine Lamp) or MIL (Malfunction Indicator Lamp) on and off. A PC based Software package called WinALDL will listen to the CLCC (Closed Loop Carburetor Control) and early CLC EFI datastreams over a fairly easy to construct interface cable that converts the 160 baud TTL serial data being transmitted by the ECM to RS232[1] or USB[2] serial data but there is not much information transmitted by these early ECMs.
1986: An upgraded version of the ALDL protocol appears which communicates at 8192 bit/s with half-duplex UART signaling. This protocol is defined in GM XDE-5024B.
1988: The Society of Automotive Engineers (SAE) recommends a standardized diagnostic connector and set of diagnostic test signals.
1991:[3] The California Air Resources Board (CARB) requires that all new vehicles sold in California in 1991 and newer vehicles have some basic OBD capability. These requirements are generally referred to as "OBD-I", though this name is not applied until the introduction of OBD-II. The data link connector and its position are not standardized, nor is the data protocol.
1994: Motivated by a desire for a statewide emissions testing program, the CARB issues the OBD-II specification and mandates that it be adopted for all cars sold in California starting in model year 1996 (see CCR Title 13 Section 1968.1 and 40 CFR Part 86 Section 86.094). The DTCs and connector suggested by the SAE are incorporated into this specification.
1996: The OBD-II specification is made mandatory for all cars manufactured in the United States to be sold in the United States.
2001: The European Union makes EOBD mandatory for all gasoline (petrol) vehicles sold in the European Union, starting in MY2001 (see European emission standards Directive 98/69/EC[4]).
2003: The European Union makes EOBD mandatory for all diesel cars sold in the European Union
2008: All cars sold in the United States are required to use the ISO 15765-4[5] signaling standard (a variant of the Controller Area Network (CAN) bus).[6]
2008: Certain light vehicles in China are required by the Environmental Protection Administration Office to implement OBD (standard GB18352[7]) by July 1, 2008.[8][9] Some regional exemptions may apply.
2010: HDOBD (heavy duty) specification is made mandatory for selected commercial (non-passenger car) engines sold in the United States.
 
 
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