Under what condition would you check the vehicle's alignment?

Checking the vehicle's alignment is essential when there is uneven tire wear. This condition often indicates that the wheels are not parallel to each other or perpendicular to the ground, leading to uneven contact with the road surface. Misalignment can cause tires to wear prematurely on one side or in specific areas, which not only shortens the lifespan of the tires but can also negatively impact handling and safety.

By identifying uneven tire wear, a mechanic can determine that an alignment check is necessary. Proper wheel alignment ensures that the vehicle handles correctly and reduces the amount of excess drag, which helps improve fuel efficiency and overall performance. The other options, such as issues with the fuel gauge, engine noise, or air conditioning, do not relate to wheel alignment, making them irrelevant in this context.