City and Bayern have already secured qualification from Group D, with the latter boasting a perfect record of five wins from as many matches thus far.
Yet Pellegrini's men are eager to atone for a 3-1 defeat to Bayern at the Etihad Stadium in October, which saw the reigning champions produce a dominant display.
"We have qualified already, but it's important we improve from the home game against Bayern Munich," said Pellegrini in a press conference on Monday.
"It's an important game."
David Silva is set to return from a calf injury for City, having last featured in a 5-2 win over CSKA Moscow on November 5.
However, Pellegrini will have to cope without left-back Gael Clichy, in addition to fellow injury victims Matija Nastasic and Stefan Jovetic, and the suspended Yaya Toure.
"Gael Clichy has a problem with his foot. It's not serious, but he could not travel," added City's Chilean manager.
"I think he will be ok for Saturday (when City host Premier League title rivals Arsenal, Clichy's former club).
"Nastasic and Jovetic (both calf) have also stayed behind, but all the other players are available, apart from Yaya Toure."
Tuesday's match sees Martin Demichelis return to Bayern, a club he spent more than seven years with earlier in his career.
"We have to play with real fire in our stomachs," added the 32-year-old defender.
"It's a great team we're playing and this is great preparation for us.
"I played here for seven and a half years and experienced a lot. Tomorrow is a very emotional day for me."
