What mode should a technician use to retrieve the Vehicle Identification Number (VIN) and calibration ID from a vehicle's ECM?

The correct approach to retrieve the Vehicle Identification Number (VIN) and calibration ID from a vehicle's ECM is to use Mode 9. This mode is specifically designed for requesting and receiving vehicle information such as the VIN, calibration ID, and other related parameters that are essential for the identification and proper diagnostics of the vehicle's emissions control systems.

Mode 9 functions within the On-Board Diagnostics II (OBD-II) framework, allowing technicians to access and display information stored in the vehicle’s electronic systems. The significance of accurately obtaining the VIN and calibration ID is crucial, as it enables the technician to reference the correct specifications, service processes, and updates specific to that vehicle.

Other modes, such as Mode 6, Mode 7, and Mode 10, serve different purposes—such as accessing specific diagnostic trouble codes, test results, or manufacturer-specific functions—but they do not provide the VIN and calibration ID, making them unsuitable for this specific inquiry. Understanding the functions of each mode helps technicians effectively navigate the diagnostic process and ensure compliance with emissions regulations.