How do you know when the tension pulley is bad on a Mazda mpv 2003?

You can determine if the tension pulley on a 2003 Mazda MPV is bad by listening for unusual noises, such as squeaking or grinding, which may indicate wear or failure. Additionally, if the serpentine belt is slipping or showing signs of excessive wear, it could be a sign that the tension pulley is not maintaining proper tension. Visually inspecting the pulley for any cracks, damage, or excessive play can also help confirm if it needs replacement. If the pulley doesn't spin freely or feels rough when turned by hand, it likely needs to be replaced.