Commercial Driver’s License (CDL) Practice Exam 2025 – All-in-One Guide to Master Your CDL Test!

A defective air suspension system can be indicated by more than three PSI of leakage in five minutes. This measurement is crucial because it demonstrates that there is a significant loss of air pressure, which is not normal for a properly functioning system. Air suspension relies on maintaining a certain level of air pressure to support the vehicle's weight and ensure a smooth ride. When the leakage exceeds this threshold, it suggests that the components, such as the air bags or lines, may be compromised, leading to potential performance issues and safety risks.

Other indicators, such as excessive noise, visible air leaks, and fluctuating pressure readings, can also suggest issues, but they are not as definitive as the PSI leakage measurement in determining a defect specifically. Excessive noise might point to problems but could stem from other sources, while visible air leaks can vary in severity. Fluctuating pressure readings might indicate a problem but lack the precise quantification that the PSI measurement provides, making the latter a more conclusive sign of a defective system.