Chicago Police Supt. Eddie Johnson is asking the city’s inspector general to look into allegations Johnson’s fiancée, a Chicago Police lieutenant, might have intervened to help her son following a traffic stop, a spokesman for the department said Tuesday.

In an emailed statement, spokesman Anthony Guglielmi said the department became aware of the incident Tuesday morning and that an internal investigation has been opened into the “handling of the traffic offense” involving the son of Lt. Nakia Fenner.

“Supt. Johnson is committed to the highest levels of integrity and professional standards for every member of the Chicago Police Department,” Guglielmi said. “He has asked Internal Affairs that this case be turned over to the Chicago Inspector General for an independent investigation into the facts to avoid any perception of impropriety.”

Rachel Leven, a spokeswoman for Inspector General Joseph Ferguson, said: “Our Office will review any information CPD provides in accordance with our procedures when we receive any complaint or referral.”

Asked Tuesday night if, prior to Tuesday, Johnson had mentioned his plans to go to the Inspector General’s Office, Fenner said: “I don’t have any comment regarding that story.”

It’s not the first time Fenner has been the subject of one of the inspector general’s investigations.

In its scathing report on Chicago’s police force, the U.S. Justice Department lifted the veil on another Ferguson investigation involving Fenner — this one into allegations of cheating prior to the August, 2015 lieutenants exam.

“The city’s inspector general is . . . currently investigating allegations that three recently-promoted lieutenants were coached by a high-ranking official who helped develop the August 2015 lieutenant’s exam,” the report states in a section devoted exclusively to CPD’s much-criticized promotion process.

“Although the investigation is ongoing, allegations of improper exam procedures make CPD officers doubt the fairness of the exam process. . . . In addition to litigation concerning the tests’ discriminatory impact, promotional exams also have been tainted with allegations of cheating and cronyism in the exam’s preparations or administration.”

Fenner was not mentioned by name in the DOJ report, but sources said the “ongoing investigation” is a reference to allegations that Eugene Williams, a former finalist for police superintendent, improperly coached Fenner and two other women, including the wife of former First Deputy Police Superintendent Al Wysinger, prior to the lieutenants’ exam.

Williams was in a unique position to assist the women, since he had helped develop the exam. He has repeatedly refused to discuss the coaching allegations, and has since retired.

All three women, including Johnson’s fiancée, were promoted after scoring well on the test. Ferguson’s office has declined to comment on that case.

Johnson’s request to Ferguson’s office comes in the wake of a health scare last week. On Friday, the 56-year-old superintendent grew lightheaded and wobbly during a press conference at a South Side police station, leading him to disclose he has high blood pressure and is on the waiting list for kidney transplant.

Contributing: Sam Charles