Under what circumstances can a test only station provide a diagnosis of an emissions-related smog check failure?

A test-only station is specifically designed to perform smog checks without diagnosing the cause of any failures. The primary role of these stations is to ensure impartiality and objectivity in performing emissions tests, thus placing restrictions on their ability to diagnose problems. Since their function is solely to conduct the emission tests, they do not have the authorization to offer diagnostic services related to emissions failures, which are typically reserved for test-and-repair facilities.

This limitation ensures that customers receive an unbiased assessment of their vehicle's emissions without any influence from repair services. The rationale behind this restriction is to maintain the integrity of the testing process, making sure that the results reflect the true status of the vehicle's compliance with emissions standards.

As such, it is clear that test-only stations cannot provide any diagnostics, reinforcing the importance of keeping testing separate from repair services to avoid conflicts of interest and ensure accurate emissions compliance evaluations.