Q: Will the Genius Bar charge me for a repair estimate or diagnostic

Vintage and obsolete products - Apple Support

I have never had Apple charge for diagnostic or repair estimates at its retail stores. However, with Mac's that are out of warranty there may be a charge for diagnosing an issue if the Mac needs to be disassembled. For simply running through Apple's hardware/software diagnostics at the genius bar, I don't believe there is a charge.

Call and ask, that is the best way to find out.

Tom