The Federal Election Commission has taken up a complaint filed by the National Legal and Policy Center that Rangel, D-N.Y., improperly used funds from his National Leadership PAC to pay for legal counsel for the House ethics case, the New York Post reported.
Congress lets members use only money from their individual campaign accounts or legal defense funds for legal fees.
Rangel, former chairman of the Ways and Means Committee, called his censure "embarrassing" and "painful" Sunday in his first television interview since the punishment.
Rangel was tried without legal representation after his attorneys at Zuckerman Spaeder dropped him in October. He said he could no longer afford them after sinking $2 million into his defense.
The NLPC complaint charges Rangel broke ethics rules by letting his PAC pay Zuckerman Spaeder $293,000 in 2010 and $100,000 to the law firm Orrick, Herrington and Sutcliffe in January 2009.
A spokeswoman for Rangel told The Hill the PAC's attorney authorized the expenditure. She also said the NLPC is "not an unbiased organization" and made "inaccurate allegations."