ok, you guys are mixing up OBD and the PCM.
First, the PCM (Powertrain Control Module, sometimes incorrectly called an ECM, ECU or ECA) is the module that controls the engine, emissions devices, and sometimes transmission. There are multiple different variations of PCMs, depending on the manufacturer and year. Some are reprogrammable, some are not.
OBD stands for OnBoard Diagnostics, generation I or generation II (and now II Enhanced). OBD is simply a set of rules and strategies that the Society of Automotive Engineers (SAE) and the federal government have agreed upon, to monitor engine condition and vehicle emissions. OBDI was implemented for the 1988 model year, and dictated that a warning lamp must be illuminated if any vehicle emission control failed. OBDII was implemented for the 1996 model year, and dictated that the warning lamp must illuminate not just for a failure, but if any condition causes the vehicle emissions to exceed 1.5 times the permitted level, and must monitor the integrity of all emission related systems for a minimum of 10 years or 100k miles. This is why sensor terminals on OBDII cars are gold plated. OBDII standards are universal for all vehicles sold in the United States, but each manufacturer has the freedom to decide how they will meet those standards. That means every brand's sensors, actuators, computers and software are different.
First, the PCM (Powertrain Control Module, sometimes incorrectly called an ECM, ECU or ECA) is the module that controls the engine, emissions devices, and sometimes transmission. There are multiple different variations of PCMs, depending on the manufacturer and year. Some are reprogrammable, some are not.
OBD stands for OnBoard Diagnostics, generation I or generation II (and now II Enhanced). OBD is simply a set of rules and strategies that the Society of Automotive Engineers (SAE) and the federal government have agreed upon, to monitor engine condition and vehicle emissions. OBDI was implemented for the 1988 model year, and dictated that a warning lamp must be illuminated if any vehicle emission control failed. OBDII was implemented for the 1996 model year, and dictated that the warning lamp must illuminate not just for a failure, but if any condition causes the vehicle emissions to exceed 1.5 times the permitted level, and must monitor the integrity of all emission related systems for a minimum of 10 years or 100k miles. This is why sensor terminals on OBDII cars are gold plated. OBDII standards are universal for all vehicles sold in the United States, but each manufacturer has the freedom to decide how they will meet those standards. That means every brand's sensors, actuators, computers and software are different.
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