Match-fixing suspicions, a PCB committee of inquiry and a probe by Pakistan's parliament have followed a tour in which Pakistan lost three test matches, five one-day internationals and a Twenty20 international.
"We found no evidence of match-fixing during our own inquiry," PCB spokesman Nadeem Sarwar said.
Sarwar said that the board, which is also in touch with the International Cricket Council over the series, has already completed its inquiry.
ICC Anti-Corruption and Security Unit chief Paul Condon has said the tour was dysfunctional and that the most likely reason for Pakistan's poor performance was conflict between rival camps of players.
Condon also said that the ICC was yet to be satisfied over the motivation for the poor play.
The PCB fined and suspended seven leading players on the recommendations of its inquiry due to ill discipline and poor performance.
Six of them have filed appeals against bans and fines.
Mohammad Yousuf did not appeal against one-year suspension and later retired from international cricket. He led Pakistan on the woeful tour of Australia.
Players launched accusations at each other in a leaked video recording of the PCB inquiry's proceedings. In the videos, former coaches Intikhab Alam and Aqib Javed questioned wicketkeeper Kamran Akmal's poor performance in the Sydney Test.
Alam told the inquiry committee he was "flabbergasted" when Akmal missed an easy run out of Shane Watson and later said he had heard stories about match fixing.
