I inquired and received word back from TurboTax that an IP PIN (Identity Protection PIN) is not needed when filing an extension request.
I'm not sure if that's the type of PIN you were asking about, since you only said "IRS PIN" and didn't respond to my first comment asking for clarification. But in any case an IP PIN is not needed for this purpose.
Please refer to the following IRS article where it says you do not need the IP PIN to request an extension.
https://www.irs.gov/individuals/understanding-your-cp01a-notice
