How far must a vehicle be driven post-battery disconnection before an emissions test?

When a vehicle's battery is disconnected, the onboard diagnostic system resets, which can affect the emissions test results. To ensure that the vehicle's systems are updated and that the readiness monitors have completed their checks, it is recommended to drive the vehicle for a specific distance. The correct distance to drive after a battery disconnection is approximately 100 miles.

During this drive, the vehicle will go through various operating conditions that allow the onboard computer to recheck and ensure that all the emissions systems are functioning properly. This process helps to guarantee that when the vehicle undergoes an emissions test, it reflects accurate data and meets the required emission standards.

Driving shorter distances might not allow all components to reset fully, leading to potential failure in the emissions test. Therefore, the guidance of 100 miles helps establish that the vehicle is in a proper state for testing.