PIN code is used as an additional security tier for cryptocurrency withdrawal requests.
You can set your cryptocurrency withdrawal 6 digits PIN Code from the Account screen à Security tab à Security Center à PIN Code.
If you enter your 6-digit PIN code incorrectly five times, your PIN will be blocked for security reasons.
Please see the requested documents and information that should be submitted to unblock your PIN code. https://bilgibankasi.pro.btcturk.com/hc/tr/articles/4419140081809-PIN-Code-Resetting
You must send the requested documents and information to support@btcturk.com from your e-mail address registered in your BtcTurk account.