What is the necessary condition for checking curb height accurately?

For accurately checking curb height, it is crucial for the vehicle to be on a level surface. This ensures that the measurements taken are not affected by any deviations in the ground, which could lead to inaccuracies. When a vehicle is positioned on an uneven surface, the difference in height due to the terrain can skew the results, making it appear as if the vehicle's suspension system is either too high or too low when it may not be.

Being on a level surface allows the technician to assess the actual distance from the ground to a specified reference point on the vehicle accurately, which is essential for performing proper suspension and alignment checks. This attention to detail helps in diagnosing issues correctly and making necessary adjustments to ensure vehicle safety and performance.