The Spaniard has been criticised for taking his foot off the gas and rotating too much after clinching the Bundesliga title with seven games to spare.
Bayern lost to Augsburg and Dortmund and managed only a 3-3 draw with Hoffenheim in their last three league games since securing the title.
“Sometimes a defeat helps to improve a team,” Guardiola told reporters on Tuesday. “Tomorrow we only have that one game though.
“We have to quickly find our form back,” said Guardiola, who helped set a league record of 53 consecutive games without a loss before it ended this month.
“When there is a game like the one against Dortmund then I have to quickly analyse why it happened. If we play against Kaiserslautern the way we did against Dortmund then we will not reach any final.”
Bayern have few injury concerns with keeper Manuel Neuer the only question mark after sustaining a thigh muscle injury on Saturday.
“He could not train today but hopefully he will be able to play tomorrow.”
Bayern are chasing an unprecedented back-to-back treble having also advanced to the Champions League semi-finals where they face nine-times European Champions Real Madrid, in Guardiola’s first season in charge.
“My players know exactly why Kaiserslautern are in the last four,” he said. “They have three great strikers.”
Kaiserslautern are fourth in the second division and have a chance of clinching promotion with four games left but Bayern’s home record in the cup is near perfect having been eliminated only once in their last 30 home Cup games.
Should holders Bayern advance they could meet again with Dortmund, who take on in-form VfL Wolfsburg later on Tuesday.
“I have a lot of passion and I have not yet been to Berlin. It will be a dream for me,” Guardiola said.
(Reporting by Karolos Grohmann, editing by Ed Osmond)