If in violation of any rule or regulation from either the SEC or PCAOB then you get the hammer, and auditors may not prepare or issue any audit report with respect to that issuer.
Remember that the PCAOB also has the authority to set, amend, update, and modify auditing, quality control, and ethical standards.
Also note that the PCAOB Auditing Standard 1215, states “the auditor must retain audit documentation for seven years from the date the auditor grants permission to use the auditor's report". And that in relation to "Inspections of Registered Public Accounting Firms", the PCAOB has the mandate and authority to conduct compliance inspections of each registered public accounting firm.
Additionally, PCAOB requires that auidt documentation and assembly of files is assembled and completed no later than 45 days following the report release date.
Furthermore, contingent fees and commissions are currently not allowed - Rule 3521.
Also, the PCAOB prevents non-audit tax transactions for services related to marketing, planning, or opining in favor of the tax treatment of a transaction.