WASHINGTON — Facing a bipartisan barrage of criticism, Wells Fargo's longtime CEO Tim Sloan struggled Tuesday to defend the bank's reputation before a skeptical House committee.

"Can you give me your personal assurance that this is the end of customer harm?" asked Rep. Patrick McHenry, R-N.C., ranking member of the House Financial Services Committee.

"I can't promise you perfection," Sloan said, but the changes the company has recently made "are going to prevent them from occurring as best we can."

Wells Fargo has admitted to a range of misdeeds over the past two years: opening millions of accounts customers didn't want or ask for, improperly repossessing thousands of cars, mistakenly foreclosing on hundreds of homeowners and miscalculating fees.

"Each time a new scandal breaks, Wells Fargo promises to get to the bottom of it. It promises it make sure it doesn't happen again," McHenry said. "But then a few months later we hear about another case of dishonest sales practices or gross mismanagement, another case of the consumer who has been harmed by the bank's business practices."

The hearing is likely a preview of the tougher conditions big banks are likely to face now that Democrats have taken control of the House. Rep. Maxine Waters, D-Calif., chairwoman of the Financial Services Committee, has vowed to increase oversight of the industry and is expected to hold a hearing featuring the CEOs of all of the big banks soon.

But San Francisco-based Wells Fargo has stood apart for drawing bipartisan rebuke, including from lawmakers who've noted that they have been bank customers for decades.

Sloan has spent years attempting to repair the bank's image, including making regular visits to Capitol Hill. As he entered the packed committee room Tuesday morning, he shook hands and greeted several lawmakers.

At the hearing, Sloan told lawmakers that Wells Fargo is on track to become among the biggest corporate givers to charity and recently raised the minimum wage for its more than 200,000 workers to $15 an hour. It has also reshuffled its executive ranks and how it assesses risk, he said.

"Wells Fargo is a better bank than it was three years ago, and we are working every day to become even better," Sloan told the packed committee room.

Yet he has faced criticism for not doing more. In one contentious exchange, Rep. Brad Sherman, D-Calif., asked Sloan whether Wells Fargo would allow disgruntled customers to sue rather than force them into arbitration. Sloan said that it didn't need to and that the bank has reached out to customers.

"So you're smart, they're dumb, you have their best interests at heart," Sherman said. "You are telling them that they are stupid for wanting to go to court."

"I don't think our customers are stupid," Sloan responded.

Waters asked whether the bank giant, which has about $2 trillion in assets, should be broken up. "You've not been able to keep Wells Fargo out of trouble. Why should Wells Fargo continue to be the size that it is?" she asked. "Is Wells Fargo too big to manage?"

"No, we're not," Sloan said.