Which mode should a technician use to erase stored Diagnostic Trouble Codes after repairing a vehicle's misfire issue?

To effectively erase stored Diagnostic Trouble Codes (DTCs) after addressing a vehicle's misfire issue, the correct mode to use is Mode 4. This mode is specifically designed for clearing DTCs that may have been set during the malfunction.

Upon completing repairs, it’s essential to erase these codes to allow the vehicle’s onboard diagnostic system to begin re-monitoring the performance of the components involved. Once the codes are cleared, the system is reset, and it can help identify if the repair effectively resolved the misfire issue by monitoring for new codes that could indicate ongoing problems.

In contrast, the other modes have different functions that do not specifically include the clearing of DTCs. This makes Mode 4 the appropriate choice for technicians needing to reset the diagnostic system following repairs.