When measuring steering wheel play, when should the engine be running?

Measuring steering wheel play while the engine is running is crucial because it ensures accurate readings of the steering system's performance. When the engine is operating, the power steering system is engaged, which allows the inspector to assess how the steering responds under normal operating conditions. Accurate measurements of play are essential for diagnosing any potential issues with the steering system, as play can significantly affect vehicle handling and safety.

In contrast, if the engine is not running, measurements may not reflect the true condition of the steering system. This can lead to incorrect assessments and potentially unsafe driving conditions, as the testing would bypass the effects of the power steering assist that typically operates while the vehicle is on.

For instance, if only manual steering systems are considered, the differences are less pronounced but can still cause misleading results. Hence, implementing engine operation during the measurement process provides a more comprehensive understanding of steering performance.