Chatham-Kent Police Const. Kenneth Miller pleaded guilty Tuesday to one count of breach of trust.
Miller, 46, was charged after the province's Special Investigations Unit began an investigation after a 33-year-old woman came forward with allegations that she was assaulted on May 4, 2013.
This was the second sexual assault allegation against the Chatham-Kent officer.
Miller was also charged with sexual assault and breach of trust in connection with an incident that occurred in August 2015.
The SIU says a woman was driven in a marked cruiser to a parking lot in the Orangewood Boulevard area where she alleges she was sexually assaulted.
Miller was suspended from duty when the investigation began on Aug. 27, 2015. He was also charged with discreditable conduct under the Police Services Act.
The hearings under the Police Services Act have been put on hold until the criminal charges have been dealt with.
The Special Investigations Unit is an arm's length agency that investigates reports involving police where there has been death, serious injury or allegations of sexual assault.
The next court date will be Oct. 31, to select a date for sentencing, likely in early 2018.