How do to read and clear codes holden astra 2001?

To read and clear trouble codes on a 2001 Holden Astra, you can use an OBD-II scanner. Plug the scanner into the vehicle's OBD-II port, typically located under the dashboard near the driver's seat. Turn the ignition to the "On" position without starting the engine, and follow the scanner's instructions to retrieve and clear the codes. If you don't have a scanner, you can also disconnect the battery for about 15 minutes to reset the system, but this will clear all stored codes and might also reset other settings.