Senegal international Mane was fined and missed Saturday's 1-1 Bundesliga draw with Hoffenheim after hitting Sane following last week's 3-0 loss at City in the first leg.
Asked if the situation could provide a rallying point for Bayern, Guardiola told reporters: "Absolutely.
"Sometimes you need conflict to make the team more together," added the Spaniard, who managed Bayern from 2013-16.
"It is not a weak point for them, it's a strong point.
"I can imagine the situation against City. The best performance for Bayern Munich will be on Wednesday night."
While City take a three-goal advantage into the second leg Guardiola said it would be dangerous to sit back.
"We have to see if we can play as we have done at home and show great courage to impose our game," Guardiola said.
"We are able to do many, many good things and they are able to do it (too). I want a team who is there to win the game. I know what it's like against Bayern. If you are a little bit passive, you will suffer."
