On-Board Diagnostics

On-board diagnostics (OBD) have been in many vehicles since the 1980s. In 1996 a new OBD II system was mandated standardizing some aspects. A scan tool plugs into the OBD II compliant 16 pin Data Link Connector (DLC). OBD II requires that the DLC be accessible from the driver’s seat. It is usually under the dash near the steering column. The scan tool retrieves any diagnostic codes that have been stored in the powertrain control module (PCM) to help diagnose the problem.