If a vehicle starts to overheat during the ASM portion of the test, what should the technician do?

When a vehicle begins to overheat during the ASM (Acceleration Simulation Mode) portion of an emissions test, it is crucial for the technician to prioritize the safety and integrity of both the vehicle and the testing process. Aborting the ASM emissions test is the appropriate action because continuing the test in an overheated condition could lead to serious damage to the engine or other components.

Overheating can indicate underlying issues, such as a malfunctioning cooling system, and proceeding with the test could exacerbate these problems. By stopping the test, the technician also ensures that accurate emissions readings are not compromised by any abnormal operating conditions caused by the overheating.

In contrast, actions such as adjusting the cooling fan or attempting to downshift the vehicle would not appropriately address the overheating issue and could potentially create further risks. Issuing a waiver without addressing the root cause of the overheating would also be irresponsible, as it does not resolve the underlying mechanical problem. Therefore, aborting the ASM emissions test is the most responsible and prudent action in this situation.