Which diagnostic tool is commonly used to read trouble codes from the engine control unit (ECU)?

The OBD-II scanner is a diagnostic tool specifically designed to interface with the engine control unit (ECU) of vehicles. It reads and interprets trouble codes that the ECU generates in response to faults detected within the vehicle’s systems. The OBD-II port is a standardized connector found in most vehicles manufactured after 1996, making the OBD-II scanner widely applicable across various makes and models.

When a fault occurs, the ECU typically logs a trouble code, which can indicate everything from minor issues to significant faults needing immediate attention. The OBD-II scanner allows technicians to quickly access these codes, analyze them, and interpret diagnostic information to aid in troubleshooting and repairs. This efficiency is essential in modern automotive diagnostics, where electronic systems play a crucial role in engine performance and overall vehicle operation.

For context, other tools such as a multimeter, compression tester, or vacuum gauge serve different diagnostic purposes. A multimeter measures electrical values, a compression tester assesses the engine's compression levels to determine its internal condition, and a vacuum gauge evaluates manifold vacuum levels, which can provide insights into engine performance but do not connect directly to the ECU to read trouble codes. These tools are valuable in their respective uses but do not replace the specific functionality of an O