Which mode will help in checking permanent trouble codes in a vehicle?

The correct choice is Mode 10, which is specifically designed for accessing permanent trouble codes in a vehicle. These permanent trouble codes are significant because they indicate faults that have been detected by the vehicle's onboard diagnostic system, which persist even after the vehicle is turned off and back on. This mode allows technicians to retrieve these codes, offering insights into issues that may not be resolved simply by clearing other temporary codes.

Understanding the distinction among the different modes can be crucial for proper diagnostics. Mode 8, for instance, is generally used for controlling specific vehicle components and functions, while Mode 6 focuses on monitoring specific diagnostic tests that have been conducted on the vehicle emissions. Mode 9 is typically used for retrieving vehicle information such as the vehicle identification number (VIN) and other important details. Hence, these modes serve different purposes and do not provide the same access to permanent trouble codes as Mode 10 does.