Automotive Service Excellence (ASE) Air Conditioner Certification Practice Exam 2026 - Free ASE Air Conditioner Practice Questions and Study Guide

The situation concerning the expansion valve revolves around its operation based on pressure changes in the system. The expansion valve is designed to regulate the flow of refrigerant into the evaporator, and it relies on a capillary tube to sense the pressure of the refrigerant vapor returning from the evaporator.

If the capillary tube is broken, it results in a loss of pressure feedback to the expansion valve. Without this necessary pressure difference, the valve cannot function as intended, leading to it shutting or closing completely. This closure prevents refrigerant from flowing into the evaporator, which is critical for the cooling process.

In this context, the other options do not accurately reflect the behavior of the expansion valve under such circumstances. For instance, fully opening would lead to unrestricted flow of refrigerant, which is not advisable in the absence of pressure; remaining in position implies some level of regulation ability, which is also negated by the failure of the capillary tube; and fluctuating would suggest varying operation, which would only occur if it could still sense pressure changes, something that isn't possible with a broken capillary tube. Thus, the natural response in the absence of pressure is for the valve to close completely.