DETROIT (AP) - Volkswagen faces daunting challenges in fixing software that enables cheating on diesel emissions tests, a task made more urgent by growing anger from customers.

DETROIT (AP) Volkswagen faces daunting challenges in fixing software that enables cheating on diesel emissions tests, a task made more urgent by growing anger from customers.

The company has set aside $7.3 billion to pay for the scandal. But experts say it's likely to cost much more as VW tries to meet U.S. clean air regulations without harming the performance of its cars.

The company says in a statement Sunday that it understands car owners are upset. But it asks for patience and says it will fix the problem as soon as possible.

Experts say VW will have to strike a careful balance to appease government regulators, make customers happy and avoid spending too much money. One analyst says a fix that includes a treatment system could cost more than $20 billion.