What companies offer a free auto repair diagnosis?

Most auto repair shops provide free repair estimates that include a brief diagnosis. Employees at auto parts stores, such as O'Reilly Auto Parts, can perform quick diagnostic checks as well. Websites such as AutoMD provide online tools to help users to diagnose their own vehicles.

In most states, auto mechanics are required to provide a written estimate, and these estimates generally must detail exactly what the dealer is going to repair or replace. Auto repair shops typically lack the capabilities of auto mechanic shops, but their employees often have tools to help drivers find the parts they need to repair their vehicles.