On Board Diagnostics – Bmw E46 99-05

On Board Diagnostics – Bmw E46 99-05

OBD II is an acronym for On-Board Diagnostics II, the second generation of on-board self-diagnostic equipment requirements. These standards were originally mandated for California vehicles. Since 1996 they have been applied to all passenger vehicles sold in the United States. On-board diagnostic capabilities are incorporated into the hardware and software of the engine control module (ECM) to monitor virtually every component that can affect vehicle emissions. OBD II works to ensure that the vehicles remain as clean as possible over their entire life. Each emission-influencing component is checked by a diagnostic routine to verify that it is functioning properly. If a problem or malfunction is detected, the OBD II system illuminates a warning light on the instrument panel to alert the driver. This malfunction indicator light (MIL) will display the phrase "Check Engine" or "Service Engine Soon." The OBD II system also stores important information about the detected malfunction so that a repair technician can accurately find and fix the problem.