Final answer:
The audible wear sensor tab in a disc brake system is located on the brake pad. It creates a noise when the brake pad wears down to a certain level, indicating the need for replacement.
Step-by-step explanation:
The audible wear sensor tab in a disc brake system is located on the brake pad. It is typically attached to the brake pad backing plate and comes into contact with the rotor when the brake pad wears down to a certain level. The purpose of the sensor tab is to create a squealing noise when the brake pad needs to be replaced, alerting the driver to take action.